diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/BaseClasses_A_BaseClass.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/BaseClasses_A_BaseClass.g.cs
index a6a2214..6a3f248 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/BaseClasses_A_BaseClass.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/BaseClasses_A_BaseClass.g.cs
@@ -29,6 +29,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TestCases_SetOnlyPropertyE303C8557E.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TestCases_SetOnlyPropertyE303C8557E.g.cs
index 56d6f17..4464043 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TestCases_SetOnlyPropertyE303C8557E.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TestCases_SetOnlyPropertyE303C8557E.g.cs
@@ -27,6 +27,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TestCases_BaseModel6634CD33B5.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TestCases_BaseModel6634CD33B5.g.cs
index fd7f330..b290e3c 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TestCases_BaseModel6634CD33B5.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TestCases_BaseModel6634CD33B5.g.cs
@@ -30,6 +30,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TypeRegistry.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TypeRegistry.g.cs
index b2cadc3..e337014 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TypeRegistry.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/TypeRegistry.g.cs
@@ -43,6 +43,7 @@ public partial class TypeRegistry : Chickensoft.Introspection.ITypeRegistry {
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildOne)] = new Chickensoft.Introspection.IdentifiableTypeMetadata("ConcreteChildOne", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildOne>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildOne>(), new Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildOne.MetatypeMetadata(), "concrete_child_one", 1), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildTwo)] = new Chickensoft.Introspection.IdentifiableTypeMetadata("ConcreteChildTwo", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildTwo>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildTwo>(), new Chickensoft.Introspection.Generator.Tests.TestCases.ConcreteChildTwo.MetatypeMetadata(), "concrete_child_two", 1), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.DerivedModel)] = new Chickensoft.Introspection.IntrospectiveTypeMetadata("DerivedModel", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.DerivedModel>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.DerivedModel>(), new Chickensoft.Introspection.Generator.Tests.TestCases.DerivedModel.MetatypeMetadata(), 1), 
+      [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.GenericStruct<>)] = new Chickensoft.Introspection.TypeMetadata("GenericStruct<T>"), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.InitArgsModel)] = new Chickensoft.Introspection.IdentifiableTypeMetadata("InitArgsModel", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.InitArgsModel>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.InitArgsModel>(), new Chickensoft.Introspection.Generator.Tests.TestCases.InitArgsModel.MetatypeMetadata(), "init_args_model", 1), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.JunkAttribute)] = new Chickensoft.Introspection.ConcreteTypeMetadata("JunkAttribute", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.JunkAttribute>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.JunkAttribute>()), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.MyContainerClass)] = new Chickensoft.Introspection.ConcreteTypeMetadata("MyContainerClass", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.MyContainerClass>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.MyContainerClass>()), 
@@ -51,6 +52,7 @@ public partial class TypeRegistry : Chickensoft.Introspection.ITypeRegistry {
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.MyType<>)] = new Chickensoft.Introspection.TypeMetadata("MyType<T>"), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.NameOfId)] = new Chickensoft.Introspection.IdentifiableTypeMetadata("NameOfId", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.NameOfId>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.NameOfId>(), new Chickensoft.Introspection.Generator.Tests.TestCases.NameOfId.MetatypeMetadata(), "NameOfId", 1), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.NoId)] = new Chickensoft.Introspection.IntrospectiveTypeMetadata("NoId", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.NoId>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.NoId>(), new Chickensoft.Introspection.Generator.Tests.TestCases.NoId.MetatypeMetadata(), 1), 
+      [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.NullablePropertyTypes)] = new Chickensoft.Introspection.IntrospectiveTypeMetadata("NullablePropertyTypes", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.NullablePropertyTypes>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.NullablePropertyTypes>(), new Chickensoft.Introspection.Generator.Tests.TestCases.NullablePropertyTypes.MetatypeMetadata(), 1), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.One.Two)] = new Chickensoft.Introspection.ConcreteTypeMetadata("Two", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two>()), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four)] = new Chickensoft.Introspection.ConcreteTypeMetadata("Four", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four>()), 
       [typeof(Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four.NestedType)] = new Chickensoft.Introspection.IdentifiableTypeMetadata("NestedType", static (r) => r.Receive<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four.NestedType>(), static () => System.Activator.CreateInstance<Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four.NestedType>(), new Chickensoft.Introspection.Generator.Tests.TestCases.One.Two.IThree.Four.NestedType.MetatypeMetadata(), "nested_type", 1), 
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/_MyContainerClass_MyModel67E837FC39.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/_MyContainerClass_MyModel67E837FC39.g.cs
index 35b91ce..11671f1 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/_MyContainerClass_MyModel67E837FC39.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/_MyContainerClass_MyModel67E837FC39.g.cs
@@ -27,12 +27,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           IsRequired: false,
           HasDefaultValue: true,
           Getter: static (object obj) => ((MyModel)obj).Age,
-          Setter: static (object obj, object? value) => ((MyModel)obj).Age = (int)value,
+          Setter: static (object obj, object? value) => ((MyModel)obj).Age = (int?)value,
           GenericType: new GenericType(
             OpenType: typeof(int),
             ClosedType: typeof(int),
+            IsNullable: true,
             Arguments: System.Array.Empty<GenericType>(),
-            GenericTypeGetter: static receiver => receiver.Receive<int>(),
+            GenericTypeGetter: static receiver => receiver.Receive<int?>(),
             GenericTypeGetter2: default
           ),
           Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -51,6 +52,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           GenericType: new GenericType(
             OpenType: typeof(string),
             ClosedType: typeof(string),
+            IsNullable: false,
             Arguments: System.Array.Empty<GenericType>(),
             GenericTypeGetter: static receiver => receiver.Receive<string>(),
             GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/er2_DeeplyNestedBaseClassAC795ED913.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/er2_DeeplyNestedBaseClassAC795ED913.g.cs
index ae3f879..afcbb22 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/er2_DeeplyNestedBaseClassAC795ED913.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/er2_DeeplyNestedBaseClassAC795ED913.g.cs
@@ -31,6 +31,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
             GenericType: new GenericType(
               OpenType: typeof(string),
               ClosedType: typeof(string),
+              IsNullable: false,
               Arguments: System.Array.Empty<GenericType>(),
               GenericTypeGetter: static receiver => receiver.Receive<string>(),
               GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/her_A_B_C_D_SomeBaseClassECA01F390E.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/her_A_B_C_D_SomeBaseClassECA01F390E.g.cs
index 779f88a..fe48607 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/her_A_B_C_D_SomeBaseClassECA01F390E.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/her_A_B_C_D_SomeBaseClassECA01F390E.g.cs
@@ -33,6 +33,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
                 GenericType: new GenericType(
                   OpenType: typeof(string),
                   ClosedType: typeof(string),
+                  IsNullable: false,
                   Arguments: System.Array.Empty<GenericType>(),
                   GenericTypeGetter: static receiver => receiver.Receive<string>(),
                   GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/or_Tests_TestCases_MyType1CDCCD6086.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/or_Tests_TestCases_MyType1CDCCD6086.g.cs
index 2b44a86..2164bf5 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/or_Tests_TestCases_MyType1CDCCD6086.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/or_Tests_TestCases_MyType1CDCCD6086.g.cs
@@ -34,6 +34,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
@@ -58,6 +59,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(int),
           ClosedType: typeof(int),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<int>(),
           GenericTypeGetter2: default
@@ -71,20 +73,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         IsRequired: false,
         HasDefaultValue: true,
         Getter: static (object obj) => ((MyType)obj).OptionalFloat,
-        Setter: static (object obj, object? value) => ((MyType)obj).OptionalFloat = (Nullable<float>)value,
+        Setter: static (object obj, object? value) => ((MyType)obj).OptionalFloat = (float?)value,
         GenericType: new GenericType(
-          OpenType: typeof(Nullable<>),
-          ClosedType: typeof(Nullable<float>),
-          Arguments: new GenericType[] {
-              new GenericType(
-                OpenType: typeof(float),
-                ClosedType: typeof(float),
-                Arguments: System.Array.Empty<GenericType>(),
-                GenericTypeGetter: static receiver => receiver.Receive<float>(),
-                GenericTypeGetter2: default
-              )
-          },
-          GenericTypeGetter: static receiver => receiver.Receive<Nullable<float>>(),
+          OpenType: typeof(float),
+          ClosedType: typeof(float),
+          IsNullable: true,
+          Arguments: System.Array.Empty<GenericType>(),
+          GenericTypeGetter: static receiver => receiver.Receive<float?>(),
           GenericTypeGetter2: default
         ),
         Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -99,12 +94,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         IsRequired: false,
         HasDefaultValue: true,
         Getter: static (object obj) => ((MyType)obj).OptionalInt,
-        Setter: static (object obj, object? value) => ((MyType)obj).OptionalInt = (int)value,
+        Setter: static (object obj, object? value) => ((MyType)obj).OptionalInt = (int?)value,
         GenericType: new GenericType(
           OpenType: typeof(int),
           ClosedType: typeof(int),
+          IsNullable: true,
           Arguments: System.Array.Empty<GenericType>(),
-          GenericTypeGetter: static receiver => receiver.Receive<int>(),
+          GenericTypeGetter: static receiver => receiver.Receive<int?>(),
           GenericTypeGetter2: default
         ),
         Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_AttributesWithNamedArgs21E465F742.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_AttributesWithNamedArgs21E465F742.g.cs
index 9620158..74b3e05 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_AttributesWithNamedArgs21E465F742.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_AttributesWithNamedArgs21E465F742.g.cs
@@ -30,6 +30,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_InitArgsModel651DDFA4A7.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_InitArgsModel651DDFA4A7.g.cs
index 620e289..cb0acbf 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_InitArgsModel651DDFA4A7.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_InitArgsModel651DDFA4A7.g.cs
@@ -26,12 +26,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         IsRequired: false,
         HasDefaultValue: false,
         Getter: static (object obj) => ((InitArgsModel)obj).Address,
-        Setter: static (object obj, object? value) => ((InitArgsModel)obj).Address = (string)value,
+        Setter: static (object obj, object? value) => ((InitArgsModel)obj).Address = (string?)value,
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: true,
           Arguments: System.Array.Empty<GenericType>(),
-          GenericTypeGetter: static receiver => receiver.Receive<string>(),
+          GenericTypeGetter: static receiver => receiver.Receive<string?>(),
           GenericTypeGetter2: default
         ),
         Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -50,6 +51,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(int),
           ClosedType: typeof(int),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<int>(),
           GenericTypeGetter2: default
@@ -70,8 +72,9 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: true,
           Arguments: System.Array.Empty<GenericType>(),
-          GenericTypeGetter: static receiver => receiver.Receive<string>(),
+          GenericTypeGetter: static receiver => receiver.Receive<string?>(),
           GenericTypeGetter2: default
         ),
         Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -90,6 +93,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(InitArgsEnum),
           ClosedType: typeof(InitArgsEnum),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<InitArgsEnum>(),
           GenericTypeGetter2: default
@@ -110,6 +114,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(InitArgsEnum),
           ClosedType: typeof(InitArgsEnum),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<InitArgsEnum>(),
           GenericTypeGetter2: default
@@ -130,6 +135,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
@@ -166,7 +172,7 @@ public object Construct(System.Collections.Generic.IReadOnlyDictionary<string, o
       args = args ?? throw new System.ArgumentNullException(nameof(args), "Constructing InitArgsModel requires init args.");
       return new InitArgsModel() {
         Age = args.ContainsKey("Age") ? (int)args["Age"] : default(int)!, 
-        Description = args.ContainsKey("Description") ? (string)args["Description"] : default(string)!, 
+        Description = args.ContainsKey("Description") ? (string?)args["Description"] : default(string?), 
         HasAttended = args.ContainsKey("HasAttended") ? (InitArgsEnum)args["HasAttended"] : InitArgsEnum.No, 
         Name = args.ContainsKey("Name") ? (string)args["Name"] : default(string)!
       };
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_PropertyModel4D221791B1.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_PropertyModel4D221791B1.g.cs
index e8cd47a..1103d58 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_PropertyModel4D221791B1.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/s_TestCases_PropertyModel4D221791B1.g.cs
@@ -27,6 +27,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ses_NullablePropertyTypesC877B09C3B.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ses_NullablePropertyTypesC877B09C3B.g.cs
new file mode 100644
index 0000000..b065249
--- /dev/null
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ses_NullablePropertyTypesC877B09C3B.g.cs
@@ -0,0 +1,199 @@
+#pragma warning disable
+#nullable enable
+namespace Chickensoft.Introspection.Generator.Tests.TestCases;
+
+using Chickensoft.Introspection;
+using Chickensoft.Introspection.Generator.Tests.TestUtils;
+using System;
+using System.Collections.Generic;
+
+partial class NullablePropertyTypes : Chickensoft.Introspection.IIntrospective {
+  [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+  public Chickensoft.Introspection.MixinBlackboard MixinState { get; } = new();
+  
+  [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+  public Chickensoft.Introspection.IMetatype Metatype => ((Chickensoft.Introspection.IIntrospectiveTypeMetadata)Chickensoft.Introspection.Types.Graph.GetMetadata(typeof(NullablePropertyTypes))).Metatype;
+  
+  public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public System.Type Type => typeof(NullablePropertyTypes);
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public bool HasInitProperties { get; } = false;
+    
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public System.Collections.Generic.IReadOnlyList<Chickensoft.Introspection.PropertyMetadata> Properties { get; } = new System.Collections.Generic.List<Chickensoft.Introspection.PropertyMetadata>() {
+      new Chickensoft.Introspection.PropertyMetadata(
+        Name: "Age",
+        IsInit: false,
+        IsRequired: false,
+        HasDefaultValue: false,
+        Getter: static (object obj) => ((NullablePropertyTypes)obj).Age,
+        Setter: static (object obj, object? value) => ((NullablePropertyTypes)obj).Age = (int?)value,
+        GenericType: new GenericType(
+          OpenType: typeof(int),
+          ClosedType: typeof(int),
+          IsNullable: true,
+          Arguments: System.Array.Empty<GenericType>(),
+          GenericTypeGetter: static receiver => receiver.Receive<int?>(),
+          GenericTypeGetter2: default
+        ),
+        Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
+          [typeof(TagAttribute)] = new System.Attribute[] {
+            new TagAttribute("age")
+          }
+        }
+      ), 
+      new Chickensoft.Introspection.PropertyMetadata(
+        Name: "Map",
+        IsInit: false,
+        IsRequired: false,
+        HasDefaultValue: false,
+        Getter: static (object obj) => ((NullablePropertyTypes)obj).Map,
+        Setter: static (object obj, object? value) => ((NullablePropertyTypes)obj).Map = (Dictionary<int, Dictionary<string, List<object?>?>?>?)value,
+        GenericType: new GenericType(
+          OpenType: typeof(Dictionary<,>),
+          ClosedType: typeof(Dictionary<int, Dictionary<string, List<object?>?>?>),
+          IsNullable: true,
+          Arguments: new GenericType[] {
+              new GenericType(
+                OpenType: typeof(int),
+                ClosedType: typeof(int),
+                IsNullable: false,
+                Arguments: System.Array.Empty<GenericType>(),
+                GenericTypeGetter: static receiver => receiver.Receive<int>(),
+                GenericTypeGetter2: default
+              ), 
+              new GenericType(
+                OpenType: typeof(Dictionary<,>),
+                ClosedType: typeof(Dictionary<string, List<object?>?>),
+                IsNullable: true,
+                Arguments: new GenericType[] {
+                    new GenericType(
+                      OpenType: typeof(string),
+                      ClosedType: typeof(string),
+                      IsNullable: false,
+                      Arguments: System.Array.Empty<GenericType>(),
+                      GenericTypeGetter: static receiver => receiver.Receive<string>(),
+                      GenericTypeGetter2: default
+                    ), 
+                    new GenericType(
+                      OpenType: typeof(List<>),
+                      ClosedType: typeof(List<object?>),
+                      IsNullable: true,
+                      Arguments: new GenericType[] {
+                          new GenericType(
+                            OpenType: typeof(object),
+                            ClosedType: typeof(object),
+                            IsNullable: true,
+                            Arguments: System.Array.Empty<GenericType>(),
+                            GenericTypeGetter: static receiver => receiver.Receive<object?>(),
+                            GenericTypeGetter2: default
+                          )
+                      },
+                      GenericTypeGetter: static receiver => receiver.Receive<List<object?>?>(),
+                      GenericTypeGetter2: default
+                    )
+                },
+                GenericTypeGetter: static receiver => receiver.Receive<Dictionary<string, List<object?>?>?>(),
+                GenericTypeGetter2: static receiver => receiver.Receive<string, List<object?>?>()
+              )
+          },
+          GenericTypeGetter: static receiver => receiver.Receive<Dictionary<int, Dictionary<string, List<object?>?>?>?>(),
+          GenericTypeGetter2: static receiver => receiver.Receive<int, Dictionary<string, List<object?>?>?>()
+        ),
+        Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
+          [typeof(TagAttribute)] = new System.Attribute[] {
+            new TagAttribute("map")
+          }
+        }
+      ), 
+      new Chickensoft.Introspection.PropertyMetadata(
+        Name: "Name",
+        IsInit: false,
+        IsRequired: false,
+        HasDefaultValue: false,
+        Getter: static (object obj) => ((NullablePropertyTypes)obj).Name,
+        Setter: static (object obj, object? value) => ((NullablePropertyTypes)obj).Name = (string?)value,
+        GenericType: new GenericType(
+          OpenType: typeof(string),
+          ClosedType: typeof(string),
+          IsNullable: true,
+          Arguments: System.Array.Empty<GenericType>(),
+          GenericTypeGetter: static receiver => receiver.Receive<string?>(),
+          GenericTypeGetter2: default
+        ),
+        Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
+          [typeof(TagAttribute)] = new System.Attribute[] {
+            new TagAttribute("name")
+          }
+        }
+      ), 
+      new Chickensoft.Introspection.PropertyMetadata(
+        Name: "Nullables",
+        IsInit: false,
+        IsRequired: false,
+        HasDefaultValue: false,
+        Getter: static (object obj) => ((NullablePropertyTypes)obj).Nullables,
+        Setter: static (object obj, object? value) => ((NullablePropertyTypes)obj).Nullables = (GenericStruct<GenericStruct<int?>?>?)value,
+        GenericType: new GenericType(
+          OpenType: typeof(GenericStruct<>),
+          ClosedType: typeof(GenericStruct<GenericStruct<int?>?>),
+          IsNullable: true,
+          Arguments: new GenericType[] {
+              new GenericType(
+                OpenType: typeof(GenericStruct<>),
+                ClosedType: typeof(GenericStruct<int?>),
+                IsNullable: true,
+                Arguments: new GenericType[] {
+                    new GenericType(
+                      OpenType: typeof(int),
+                      ClosedType: typeof(int),
+                      IsNullable: true,
+                      Arguments: System.Array.Empty<GenericType>(),
+                      GenericTypeGetter: static receiver => receiver.Receive<int?>(),
+                      GenericTypeGetter2: default
+                    )
+                },
+                GenericTypeGetter: static receiver => receiver.Receive<GenericStruct<int?>?>(),
+                GenericTypeGetter2: default
+              )
+          },
+          GenericTypeGetter: static receiver => receiver.Receive<GenericStruct<GenericStruct<int?>?>?>(),
+          GenericTypeGetter2: default
+        ),
+        Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
+          [typeof(TagAttribute)] = new System.Attribute[] {
+            new TagAttribute("map_verbose")
+          }
+        }
+      )
+    };
+    
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public System.Collections.Generic.IReadOnlyDictionary<System.Type, System.Attribute[]> Attributes { get; } = new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
+      [typeof(MetaAttribute)] = new System.Attribute[] {
+        new MetaAttribute()
+      }
+    };
+    
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public System.Collections.Generic.IReadOnlyList<System.Type> Mixins { get; } = new System.Collections.Generic.List<System.Type>() {
+    };
+    
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public System.Collections.Generic.IReadOnlyDictionary<System.Type, System.Action<object>> MixinHandlers { get; } = new System.Collections.Generic.Dictionary<System.Type, System.Action<object>>() {
+    };
+    
+    
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public object Construct(System.Collections.Generic.IReadOnlyDictionary<string, object?>? args = null) {
+      return new NullablePropertyTypes();
+    }
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public override bool Equals(object obj) => true;
+    [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
+    public override int GetHashCode() => base.GetHashCode();
+  }
+}
+#nullable restore
+#pragma warning restore
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/sts_TestCases_Collections23D60571D5.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/sts_TestCases_Collections23D60571D5.g.cs
index 7b52abf..08eafb4 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/sts_TestCases_Collections23D60571D5.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/sts_TestCases_Collections23D60571D5.g.cs
@@ -30,14 +30,17 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(Dictionary<,>),
           ClosedType: typeof(Dictionary<List<string>, List<List<int>>>),
+          IsNullable: false,
           Arguments: new GenericType[] {
               new GenericType(
                 OpenType: typeof(List<>),
                 ClosedType: typeof(List<string>),
+                IsNullable: false,
                 Arguments: new GenericType[] {
                     new GenericType(
                       OpenType: typeof(string),
                       ClosedType: typeof(string),
+                      IsNullable: false,
                       Arguments: System.Array.Empty<GenericType>(),
                       GenericTypeGetter: static receiver => receiver.Receive<string>(),
                       GenericTypeGetter2: default
@@ -49,14 +52,17 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
               new GenericType(
                 OpenType: typeof(List<>),
                 ClosedType: typeof(List<List<int>>),
+                IsNullable: false,
                 Arguments: new GenericType[] {
                     new GenericType(
                       OpenType: typeof(List<>),
                       ClosedType: typeof(List<int>),
+                      IsNullable: false,
                       Arguments: new GenericType[] {
                           new GenericType(
                             OpenType: typeof(int),
                             ClosedType: typeof(int),
+                            IsNullable: false,
                             Arguments: System.Array.Empty<GenericType>(),
                             GenericTypeGetter: static receiver => receiver.Receive<int>(),
                             GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_DerivedModel2583598D69.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_DerivedModel2583598D69.g.cs
index ea77808..8384dd0 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_DerivedModel2583598D69.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_DerivedModel2583598D69.g.cs
@@ -30,6 +30,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(int),
           ClosedType: typeof(int),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<int>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_PartialModelED2F9C08D8.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_PartialModelED2F9C08D8.g.cs
index d58a770..52f2a46 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_PartialModelED2F9C08D8.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/ts_TestCases_PartialModelED2F9C08D8.g.cs
@@ -30,6 +30,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(int),
           ClosedType: typeof(int),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<int>(),
           GenericTypeGetter2: default
@@ -50,6 +51,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
         GenericType: new GenericType(
           OpenType: typeof(string),
           ClosedType: typeof(string),
+          IsNullable: false,
           Arguments: System.Array.Empty<GenericType>(),
           GenericTypeGetter: static receiver => receiver.Receive<string>(),
           GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/wo_IThree_Four_NestedType7FDE758058.g.cs b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/wo_IThree_Four_NestedType7FDE758058.g.cs
index eb01953..4598dfb 100644
--- a/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/wo_IThree_Four_NestedType7FDE758058.g.cs
+++ b/Chickensoft.Introspection.Generator.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/wo_IThree_Four_NestedType7FDE758058.g.cs
@@ -38,6 +38,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
                 GenericType: new GenericType(
                   OpenType: typeof(string),
                   ClosedType: typeof(string),
+                  IsNullable: false,
                   Arguments: System.Array.Empty<GenericType>(),
                   GenericTypeGetter: static receiver => receiver.Receive<string>(),
                   GenericTypeGetter2: default
@@ -58,12 +59,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
                 IsRequired: false,
                 HasDefaultValue: true,
                 Getter: static (object obj) => ((NestedType)obj).OptionalFloat,
-                Setter: static (object obj, object? value) => ((NestedType)obj).OptionalFloat = (float)value,
+                Setter: static (object obj, object? value) => ((NestedType)obj).OptionalFloat = (float?)value,
                 GenericType: new GenericType(
                   OpenType: typeof(float),
                   ClosedType: typeof(float),
+                  IsNullable: true,
                   Arguments: System.Array.Empty<GenericType>(),
-                  GenericTypeGetter: static receiver => receiver.Receive<float>(),
+                  GenericTypeGetter: static receiver => receiver.Receive<float?>(),
                   GenericTypeGetter2: default
                 ),
                 Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -78,12 +80,13 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
                 IsRequired: false,
                 HasDefaultValue: true,
                 Getter: static (object obj) => ((NestedType)obj).OptionalInt,
-                Setter: static (object obj, object? value) => ((NestedType)obj).OptionalInt = (int)value,
+                Setter: static (object obj, object? value) => ((NestedType)obj).OptionalInt = (int?)value,
                 GenericType: new GenericType(
                   OpenType: typeof(int),
                   ClosedType: typeof(int),
+                  IsNullable: true,
                   Arguments: System.Array.Empty<GenericType>(),
-                  GenericTypeGetter: static receiver => receiver.Receive<int>(),
+                  GenericTypeGetter: static receiver => receiver.Receive<int?>(),
                   GenericTypeGetter2: default
                 ),
                 Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
diff --git a/Chickensoft.Introspection.Generator.Tests/test/src/models/DeclaredPropertyTest.cs b/Chickensoft.Introspection.Generator.Tests/test/src/models/DeclaredPropertyTest.cs
index e17e539..0047633 100644
--- a/Chickensoft.Introspection.Generator.Tests/test/src/models/DeclaredPropertyTest.cs
+++ b/Chickensoft.Introspection.Generator.Tests/test/src/models/DeclaredPropertyTest.cs
@@ -17,7 +17,7 @@ public void Equality() {
       IsNullable: false,
       DefaultValueExpression: null,
       GenericType: new GenericTypeNode(
-        "System.String", Children: ImmutableArray<GenericTypeNode>.Empty
+        "System.String", false, Children: ImmutableArray<GenericTypeNode>.Empty
       ),
       Attributes: ImmutableArray<DeclaredAttribute>.Empty
     );
@@ -36,7 +36,7 @@ public void Equality() {
         IsNullable: false,
         DefaultValueExpression: null,
         GenericType: new GenericTypeNode(
-          "System.String", Children: ImmutableArray<GenericTypeNode>.Empty
+          "System.String", false, Children: ImmutableArray<GenericTypeNode>.Empty
         ),
         Attributes: ImmutableArray<DeclaredAttribute>.Empty
       )
@@ -51,7 +51,7 @@ public void Equality() {
       IsNullable: false,
       DefaultValueExpression: null,
       GenericType: new GenericTypeNode(
-        "System.String", Children: ImmutableArray<GenericTypeNode>.Empty
+        "System.String", false, Children: ImmutableArray<GenericTypeNode>.Empty
       ),
       Attributes: new DeclaredAttribute[] {
         new("", ImmutableArray<string>.Empty, ImmutableArray<string>.Empty)
@@ -66,7 +66,7 @@ public void Equality() {
         IsNullable: false,
         DefaultValueExpression: null,
         GenericType: new GenericTypeNode(
-          "System.String", Children: ImmutableArray<GenericTypeNode>.Empty
+          "System.String", false, Children: ImmutableArray<GenericTypeNode>.Empty
         ),
         Attributes: ImmutableArray<DeclaredAttribute>.Empty
       )
diff --git a/Chickensoft.Introspection.Generator.Tests/test/src/models/GenericTypeNodeTest.cs b/Chickensoft.Introspection.Generator.Tests/test/src/models/GenericTypeNodeTest.cs
index f29092b..61358c9 100644
--- a/Chickensoft.Introspection.Generator.Tests/test/src/models/GenericTypeNodeTest.cs
+++ b/Chickensoft.Introspection.Generator.Tests/test/src/models/GenericTypeNodeTest.cs
@@ -9,7 +9,7 @@ public class GenericTypeNodeTest {
   [Fact]
   public void Equality() {
     var node = new GenericTypeNode(
-      "Type", ImmutableArray<GenericTypeNode>.Empty
+      "Type", false, ImmutableArray<GenericTypeNode>.Empty
     );
 
     node.Equals(null).ShouldBeFalse();
diff --git a/Chickensoft.Introspection.Generator.Tests/test_cases/NullablePropertyTypes.cs b/Chickensoft.Introspection.Generator.Tests/test_cases/NullablePropertyTypes.cs
new file mode 100644
index 0000000..4ff8543
--- /dev/null
+++ b/Chickensoft.Introspection.Generator.Tests/test_cases/NullablePropertyTypes.cs
@@ -0,0 +1,28 @@
+namespace Chickensoft.Introspection.Generator.Tests.TestCases;
+
+using System;
+using System.Collections.Generic;
+using Chickensoft.Introspection;
+using Chickensoft.Introspection.Generator.Tests.TestUtils;
+
+public struct GenericStruct<T> {
+  public T Value { get; set; }
+}
+
+[Meta]
+public partial class NullablePropertyTypes {
+  [Tag("name")]
+  public string? Name { get; set; }
+
+  [Tag("age")]
+  public int? Age { get; set; }
+
+  // All types are nullable (except dictionary keys int and string)
+  [Tag("map")]
+  public Dictionary<int, Dictionary<string, List<object?>?>?>? Map { get; set; }
+
+#pragma warning disable IDE0001
+  [Tag("map_verbose")]
+  public Nullable<GenericStruct<Nullable<GenericStruct<int?>>>> Nullables { get; set; }
+#pragma warning restore IDE0001
+}
diff --git a/Chickensoft.Introspection.Generator/src/TypeGenerator.cs b/Chickensoft.Introspection.Generator/src/TypeGenerator.cs
index 33da474..ffe3150 100644
--- a/Chickensoft.Introspection.Generator/src/TypeGenerator.cs
+++ b/Chickensoft.Introspection.Generator/src/TypeGenerator.cs
@@ -531,28 +531,15 @@ TypeDeclarationSyntax type
 
       hasSetter = hasSetter || isInit;
 
-      var isNullable =
-        property.Type is NullableTypeSyntax ||
-        (
-          property.Type is GenericNameSyntax generic &&
-          generic.Identifier.ValueText == "Nullable"
-        );
+      var propType = property.Type;
+
+      var isNullable = propType.IsNullable();
+      propType = property.Type.UnwrapNullable();
 
       var defaultValueExpression =
         property.Initializer?.Value.NormalizeWhitespace().ToString();
 
-      var propType = property.Type;
-
-      if (property.Type is NullableTypeSyntax nullableType) {
-        propType = nullableType.ElementType;
-      }
-
-      var genericType = propType is GenericNameSyntax genericSyntax
-        ? GenericTypeNode.Create(genericSyntax)
-        : new GenericTypeNode(
-          Type: propType.NormalizeWhitespace().ToString(),
-          Children: ImmutableArray<GenericTypeNode>.Empty
-        );
+      var genericType = GenericTypeNode.Create(propType, isNullable);
 
       properties.Add(
         new DeclaredProperty(
diff --git a/Chickensoft.Introspection.Generator/src/models/DeclaredProperty.cs b/Chickensoft.Introspection.Generator/src/models/DeclaredProperty.cs
index bc3786f..6ece2b7 100644
--- a/Chickensoft.Introspection.Generator/src/models/DeclaredProperty.cs
+++ b/Chickensoft.Introspection.Generator/src/models/DeclaredProperty.cs
@@ -37,13 +37,15 @@ public void Write(IndentedTextWriter writer, string typeSimpleNameClosed) {
       ? $"static (object obj) => (({typeSimpleNameClosed})obj).{Name}"
       : "null";
 
+    var type = GenericType.ClosedType;
+
     var setter = HasSetter
       ? (
         IsInit
           ? "null"
           : $"static (object obj, object? value) => " +
             $"(({typeSimpleNameClosed})obj)" +
-            $".{Name} = ({GenericType.ClosedType}){propertyValue}"
+            $".{Name} = ({type}){propertyValue}"
       )
       : "null";
 
diff --git a/Chickensoft.Introspection.Generator/src/models/DeclaredType.cs b/Chickensoft.Introspection.Generator/src/models/DeclaredType.cs
index 4099d27..e2e22d9 100644
--- a/Chickensoft.Introspection.Generator/src/models/DeclaredType.cs
+++ b/Chickensoft.Introspection.Generator/src/models/DeclaredType.cs
@@ -557,10 +557,17 @@ IEnumerable<DeclaredType> baseTypes
     var propStrings = allProperties
       .Where(prop => prop.IsInit || prop.IsRequired)
       .Select(
-        (prop) =>
-          $"{prop.Name} = args.ContainsKey(\"{prop.Name}\") " +
-          $"? ({prop.GenericType.ClosedType})args[\"{prop.Name}\"] : " +
-          $"{(prop.DefaultValueExpression is { } value ? value : $"default({prop.GenericType.ClosedType})!")}"
+        (prop) => {
+          var bang = prop.GenericType.IsNullable ? "" : "!";
+          return
+            $"{prop.Name} = args.ContainsKey(\"{prop.Name}\") " +
+            $"? ({prop.GenericType.ClosedType})args[\"{prop.Name}\"] : " +
+            $"{(
+            prop.DefaultValueExpression is { } value
+              ? value
+              : $"default({prop.GenericType.ClosedType}){bang}"
+            )}";
+        }
       );
 
     writer.WriteCommaSeparatedList(
diff --git a/Chickensoft.Introspection.Generator/src/models/GenericTypeNode.cs b/Chickensoft.Introspection.Generator/src/models/GenericTypeNode.cs
index 299d77d..41df54f 100644
--- a/Chickensoft.Introspection.Generator/src/models/GenericTypeNode.cs
+++ b/Chickensoft.Introspection.Generator/src/models/GenericTypeNode.cs
@@ -15,6 +15,7 @@ namespace Chickensoft.Introspection.Generator.Models;
 // types that comprise it.
 public sealed record GenericTypeNode(
   string Type,
+  bool IsNullable,
   ImmutableArray<GenericTypeNode> Children
 ) {
   /// <summary>
@@ -23,39 +24,52 @@ ImmutableArray<GenericTypeNode> Children
   /// </summary>
   public string ClosedType => Type + TypeReference.GetGenerics(
     Children.Select(child => child.ClosedType).ToImmutableArray()
-  );
+  ) + Q;
+
+  public string OpenType =>
+    Type + TypeReference.GetOpenGenerics(Children.Length) + Q;
+
+  private string Q => IsNullable ? "?" : "";
 
   /// <summary>
   /// Recursively constructs a generic type node from a generic name syntax.
   /// </summary>
-  /// <param name="genericName">Generic name syntax.</param>
+  /// <param name="typeSyntax">Generic name syntax.</param>
   /// <returns>Generic type node tree.</returns>
-  public static GenericTypeNode Create(GenericNameSyntax genericName) {
-    var type = genericName.Identifier.NormalizeWhitespace().ToString();
-
-    var children = genericName.TypeArgumentList.Arguments
-      .Select(arg => arg switch {
-        GenericNameSyntax genericNameSyntax => Create(genericNameSyntax),
-        _ => new GenericTypeNode(
-          arg.NormalizeWhitespace().ToString(),
-          ImmutableArray<GenericTypeNode>.Empty
-        )
+  public static GenericTypeNode Create(
+    TypeSyntax typeSyntax, bool isNullable
+  ) {
+    isNullable = isNullable || typeSyntax.IsNullable();
+    typeSyntax = typeSyntax.UnwrapNullable();
+
+    if (typeSyntax is not GenericNameSyntax genericNameSyntax) {
+      return new GenericTypeNode(
+        typeSyntax.NormalizeWhitespace().ToString(),
+        IsNullable: isNullable,
+        Children: ImmutableArray<GenericTypeNode>.Empty
+      );
+    }
+
+    var type = genericNameSyntax.Identifier.NormalizeWhitespace().ToString();
+
+    var children = genericNameSyntax.TypeArgumentList.Arguments
+      .Select(arg => {
+        typeSyntax = typeSyntax.UnwrapNullable();
+        isNullable = arg.IsNullable();
+
+        return Create(arg, isNullable);
       })
       .ToImmutableArray();
 
-    return new GenericTypeNode(type, children);
+    return new GenericTypeNode(type, isNullable, children);
   }
 
   public void Write(IndentedTextWriter writer) {
-    var openType = Type + TypeReference.GetOpenGenerics(Children.Length);
-    var closedType = Type + TypeReference.GetGenerics(
-      Children.Select(child => child.ClosedType).ToImmutableArray()
-    );
-
     writer.WriteLine("new GenericType(");
     writer.Indent++;
-    writer.WriteLine($"OpenType: typeof({openType.TrimEnd('?')}),");
-    writer.WriteLine($"ClosedType: typeof({closedType.TrimEnd('?')}),");
+    writer.WriteLine($"OpenType: typeof({OpenType.TrimEnd('?')}),");
+    writer.WriteLine($"ClosedType: typeof({ClosedType.TrimEnd('?')}),");
+    writer.WriteLine($"IsNullable: {(IsNullable ? "true" : "false")},");
 
     if (Children.Length > 0) {
       writer.WriteLine("Arguments: new GenericType[] {");
@@ -76,7 +90,7 @@ public void Write(IndentedTextWriter writer) {
 
     writer.WriteLine(
       "GenericTypeGetter: static receiver => " +
-      $"receiver.Receive<{closedType}>(),"
+      $"receiver.Receive<{ClosedType}>(),"
     );
     if (Children.Length >= 2) {
       writer.WriteLine(
diff --git a/Chickensoft.Introspection.Generator/src/utils/Extensions.cs b/Chickensoft.Introspection.Generator/src/utils/Extensions.cs
new file mode 100644
index 0000000..e27406c
--- /dev/null
+++ b/Chickensoft.Introspection.Generator/src/utils/Extensions.cs
@@ -0,0 +1,22 @@
+namespace Chickensoft.Introspection.Generator.Utils;
+
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+public static class Extensions {
+  public static bool IsNullable(this TypeSyntax type) {
+    return type is NullableTypeSyntax || (
+      type is GenericNameSyntax generic &&
+      generic.Identifier.ValueText == "Nullable"
+    );
+  }
+
+  public static TypeSyntax UnwrapNullable(this TypeSyntax type) {
+    return type switch {
+      NullableTypeSyntax nullable => nullable.ElementType,
+      GenericNameSyntax generic
+        when generic.Identifier.ValueText == "Nullable" =>
+          generic.TypeArgumentList.Arguments.First(),
+      _ => type
+    };
+  }
+}
diff --git a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TypeGraphTest_Model4FF6A4782E.g.cs b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TypeGraphTest_Model4FF6A4782E.g.cs
index 1803b5f..a010f1e 100644
--- a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TypeGraphTest_Model4FF6A4782E.g.cs
+++ b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/Tests_TypeGraphTest_Model4FF6A4782E.g.cs
@@ -37,6 +37,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           GenericType: new GenericType(
             OpenType: typeof(string),
             ClosedType: typeof(string),
+            IsNullable: false,
             Arguments: System.Array.Empty<GenericType>(),
             GenericTypeGetter: static receiver => receiver.Receive<string>(),
             GenericTypeGetter2: default
diff --git a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/erMetadataTest_ChildModelD70FB8BF24.g.cs b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/erMetadataTest_ChildModelD70FB8BF24.g.cs
index c76dd5c..8be1705 100644
--- a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/erMetadataTest_ChildModelD70FB8BF24.g.cs
+++ b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/erMetadataTest_ChildModelD70FB8BF24.g.cs
@@ -37,8 +37,9 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           GenericType: new GenericType(
             OpenType: typeof(string),
             ClosedType: typeof(string),
+            IsNullable: true,
             Arguments: System.Array.Empty<GenericType>(),
-            GenericTypeGetter: static receiver => receiver.Receive<string>(),
+            GenericTypeGetter: static receiver => receiver.Receive<string?>(),
             GenericTypeGetter2: default
           ),
           Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -70,8 +71,8 @@ public object Construct(System.Collections.Generic.IReadOnlyDictionary<string, o
         args = args ?? throw new System.ArgumentNullException(nameof(args), "Constructing ChildModel requires init args.");
         return new ChildModel() {
           Age = args.ContainsKey("Age") ? (int)args["Age"] : default(int)!, 
-          ChildName = args.ContainsKey("ChildName") ? (string)args["ChildName"] : default(string)!, 
-          Name = args.ContainsKey("Name") ? (string)args["Name"] : default(string)!
+          ChildName = args.ContainsKey("ChildName") ? (string?)args["ChildName"] : default(string?), 
+          Name = args.ContainsKey("Name") ? (string?)args["Name"] : default(string?)
         };
       }
       [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
diff --git a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/hMemberMetadataTest_Model8D28D57DDD.g.cs b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/hMemberMetadataTest_Model8D28D57DDD.g.cs
index 5acddff..7f9b234 100644
--- a/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/hMemberMetadataTest_Model8D28D57DDD.g.cs
+++ b/Chickensoft.Introspection.Tests/.generated/Chickensoft.Introspection.Generator/Chickensoft.Introspection.Generator.TypeGenerator/hMemberMetadataTest_Model8D28D57DDD.g.cs
@@ -37,6 +37,7 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           GenericType: new GenericType(
             OpenType: typeof(int),
             ClosedType: typeof(int),
+            IsNullable: false,
             Arguments: System.Array.Empty<GenericType>(),
             GenericTypeGetter: static receiver => receiver.Receive<int>(),
             GenericTypeGetter2: default
@@ -57,8 +58,9 @@ public class MetatypeMetadata : Chickensoft.Introspection.IMetatype {
           GenericType: new GenericType(
             OpenType: typeof(string),
             ClosedType: typeof(string),
+            IsNullable: true,
             Arguments: System.Array.Empty<GenericType>(),
-            GenericTypeGetter: static receiver => receiver.Receive<string>(),
+            GenericTypeGetter: static receiver => receiver.Receive<string?>(),
             GenericTypeGetter2: default
           ),
           Attributes: new System.Collections.Generic.Dictionary<System.Type, System.Attribute[]>() {
@@ -90,7 +92,7 @@ public object Construct(System.Collections.Generic.IReadOnlyDictionary<string, o
         args = args ?? throw new System.ArgumentNullException(nameof(args), "Constructing Model requires init args.");
         return new Model() {
           Age = args.ContainsKey("Age") ? (int)args["Age"] : default(int)!, 
-          Name = args.ContainsKey("Name") ? (string)args["Name"] : default(string)!
+          Name = args.ContainsKey("Name") ? (string?)args["Name"] : default(string?)
         };
       }
       [System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
diff --git a/Chickensoft.Introspection.Tests/test/models/GenericTypeTest.cs b/Chickensoft.Introspection.Tests/test/models/GenericTypeTest.cs
index 96f5174..1573dce 100644
--- a/Chickensoft.Introspection.Tests/test/models/GenericTypeTest.cs
+++ b/Chickensoft.Introspection.Tests/test/models/GenericTypeTest.cs
@@ -8,6 +8,7 @@ public class GenericTypeTest {
   private readonly GenericType _type = new(
     OpenType: typeof(string),
     ClosedType: typeof(string),
+    IsNullable: false,
     Arguments: [],
     GenericTypeGetter: receiver => receiver.Receive<string>(),
     GenericTypeGetter2: (_) => throw new NotImplementedException()
diff --git a/Chickensoft.Introspection.Tests/test/models/PropertyMetadataTest.cs b/Chickensoft.Introspection.Tests/test/models/PropertyMetadataTest.cs
index f672304..397ca83 100644
--- a/Chickensoft.Introspection.Tests/test/models/PropertyMetadataTest.cs
+++ b/Chickensoft.Introspection.Tests/test/models/PropertyMetadataTest.cs
@@ -13,7 +13,7 @@ public void Initializes() {
       HasDefaultValue: false,
       Getter: _ => "Value",
       Setter: (_, _) => { },
-      GenericType: new GenericType(typeof(string), typeof(string), [], _ => { }, _ => { }),
+      GenericType: new GenericType(typeof(string), typeof(string), false, [], _ => { }, _ => { }),
       Attributes: []
     );
 
diff --git a/Chickensoft.Introspection/src/models/GenericType.cs b/Chickensoft.Introspection/src/models/GenericType.cs
index 616d503..4da0410 100644
--- a/Chickensoft.Introspection/src/models/GenericType.cs
+++ b/Chickensoft.Introspection/src/models/GenericType.cs
@@ -3,18 +3,23 @@ namespace Chickensoft.Introspection;
 using System;
 
 /// <summary>
-/// Generic type representation.
+/// Type representation.
 /// </summary>
-/// <param name="OpenType">Open generic type.</param>
-/// <param name="ClosedType">Closed generic type.</param>
-/// <param name="Arguments">Type arguments.</param>
+/// <param name="OpenType">Open generic type, if generic. Otherwise the same
+/// as <see cref="ClosedType"/>.</param>
+/// <param name="ClosedType">Closed generic type, if generic. Otherwise just the
+/// plain type.</param>
+/// <param name="IsNullable">True if the type is nullable.</param>
+/// <param name="Arguments">Type arguments, if any.</param>
 /// <param name="GenericTypeGetter">Action which invokes the generic type
-/// receiver with the generic type.</param>
+/// receiver with the type.</param>
 /// <param name="GenericTypeGetter2">Action which invokes the generic type
-/// receiver with its two child generic types.</param>
+/// receiver with its two child type arguments, if present. Obviously only
+/// applies to types with exactly two type parameters.</param>
 public record GenericType(
   Type OpenType,
   Type ClosedType,
+  bool IsNullable,
   GenericType[] Arguments,
   Action<ITypeReceiver> GenericTypeGetter,
   Action<ITypeReceiver2>? GenericTypeGetter2