diff --git a/src/nodes/typeNodes/NestedTypeNode.ts b/src/nodes/typeNodes/NestedTypeNode.ts
index 0ce90c36..01cc4ca6 100644
--- a/src/nodes/typeNodes/NestedTypeNode.ts
+++ b/src/nodes/typeNodes/NestedTypeNode.ts
@@ -1,6 +1,7 @@
+import { Node, isNode } from '../Node';
 import { FixedSizeTypeNode } from './FixedSizeTypeNode';
 import { SizePrefixTypeNode } from './SizePrefixTypeNode';
-import { TypeNode } from './TypeNode';
+import { TYPE_NODES, TypeNode } from './TypeNode';
 
 export type NestedTypeNode<TType extends TypeNode> =
   | TType
@@ -44,13 +45,12 @@ export function transformNestedTypeNode<
   }
 }
 
-export function isNestedTypeNode<TType extends TypeNode>(
-  typeNode: TypeNode
-): typeNode is NestedTypeNode<TType> {
-  // const kinds = Array.isArray(kind) ? kind : [kind];
-  // return !!node && (kinds as NodeKind[]).includes(node.kind);
-  return (
-    typeNode.kind === 'fixedSizeTypeNode' ||
-    typeNode.kind === 'sizePrefixTypeNode'
-  );
+export function isNestedTypeNode<TKind extends TypeNode['kind']>(
+  node: Node | null | undefined,
+  kind: TKind | TKind[]
+): node is NestedTypeNode<Extract<TypeNode, { kind: TKind }>> {
+  if (!isNode(node, TYPE_NODES)) return false;
+  const kinds = Array.isArray(kind) ? kind : [kind];
+  const resolved = resolveNestedTypeNode(node);
+  return !!node && kinds.includes(resolved.kind as TKind);
 }
diff --git a/test/nodes/typeNodes/NestedTypeNode.test.ts b/test/nodes/typeNodes/NestedTypeNode.test.ts
new file mode 100644
index 00000000..0bb88546
--- /dev/null
+++ b/test/nodes/typeNodes/NestedTypeNode.test.ts
@@ -0,0 +1,54 @@
+import test from 'ava';
+import {
+  fixedSizeTypeNode,
+  isNestedTypeNode,
+  numberTypeNode,
+  publicKeyTypeNode,
+  resolveNestedTypeNode,
+  sizePrefixTypeNode,
+  stringTypeNode,
+  transformNestedTypeNode,
+} from '../../../src';
+
+test('it resolved nested type nodes', (t) => {
+  const node = sizePrefixTypeNode(
+    fixedSizeTypeNode(stringTypeNode(), 32),
+    numberTypeNode('u8')
+  );
+  t.deepEqual(resolveNestedTypeNode(node), stringTypeNode());
+});
+
+test('it returns the same instance when resolving nested types nodes', (t) => {
+  const node = numberTypeNode('u8');
+  t.is(resolveNestedTypeNode(node), node);
+});
+
+test('it transforms nested type nodes', (t) => {
+  const node = sizePrefixTypeNode(
+    fixedSizeTypeNode(stringTypeNode(), 32),
+    numberTypeNode('u8')
+  );
+  const transformedNode = transformNestedTypeNode(node, () =>
+    publicKeyTypeNode()
+  );
+  t.deepEqual(
+    transformedNode,
+    sizePrefixTypeNode(
+      fixedSizeTypeNode(publicKeyTypeNode(), 32),
+      numberTypeNode('u8')
+    )
+  );
+});
+
+test('it checks if a node is a nested type', (t) => {
+  const flatNode = numberTypeNode('u64');
+  t.true(isNestedTypeNode(flatNode, 'numberTypeNode'));
+  t.false(isNestedTypeNode(flatNode, 'stringTypeNode'));
+
+  const nestedNode = sizePrefixTypeNode(
+    fixedSizeTypeNode(numberTypeNode('u64'), 32),
+    numberTypeNode('u8')
+  );
+  t.true(isNestedTypeNode(nestedNode, 'numberTypeNode'));
+  t.false(isNestedTypeNode(nestedNode, 'stringTypeNode'));
+});
diff --git a/test/nodes/typeNodes/TypeNode.typetest.ts b/test/nodes/typeNodes/NestedTypeNode.typetest.ts
similarity index 94%
rename from test/nodes/typeNodes/TypeNode.typetest.ts
rename to test/nodes/typeNodes/NestedTypeNode.typetest.ts
index 131d6f84..6bc76b10 100644
--- a/test/nodes/typeNodes/TypeNode.typetest.ts
+++ b/test/nodes/typeNodes/NestedTypeNode.typetest.ts
@@ -9,7 +9,7 @@ import {
 } from '../../../src';
 
 {
-  // [ResolveNestedTypeNode]: it constraints the nested type of a node.
+  // [NestedTypeNode]: it constraints the nested type of a node.
   const stringNestedNode = fixedSizeTypeNode(stringTypeNode(), 32);
   const numberNestedNode = fixedSizeTypeNode(numberTypeNode('u32'), 32);
   stringNestedNode satisfies NestedTypeNode<StringTypeNode>;
diff --git a/test/nodes/typeNodes/TypeNode.test.ts b/test/nodes/typeNodes/TypeNode.test.ts
deleted file mode 100644
index 58d0e8c4..00000000
--- a/test/nodes/typeNodes/TypeNode.test.ts
+++ /dev/null
@@ -1,21 +0,0 @@
-import test from 'ava';
-import {
-  fixedSizeTypeNode,
-  numberTypeNode,
-  resolveNestedTypeNode,
-  sizePrefixTypeNode,
-  stringTypeNode,
-} from '../../../src';
-
-test('it resolved nested type nodes', (t) => {
-  const node = sizePrefixTypeNode(
-    fixedSizeTypeNode(stringTypeNode(), 32),
-    numberTypeNode('u8')
-  );
-  t.deepEqual(resolveNestedTypeNode(node), stringTypeNode());
-});
-
-test('it returns the same instance when resolving nested types nodes', (t) => {
-  const node = numberTypeNode('u8');
-  t.is(resolveNestedTypeNode(node), node);
-});