diff --git a/pytensor/graph/basic.py b/pytensor/graph/basic.py
index 057341909c..ed1ad6b6c2 100644
--- a/pytensor/graph/basic.py
+++ b/pytensor/graph/basic.py
@@ -710,7 +710,7 @@ def clone(self, **kwargs):
         return cp
 
 
-class NominalVariable(AtomicVariable[_TypeType]):
+class NominalVariable(Generic[_TypeType, _IdType], AtomicVariable[_TypeType]):
     """A variable that enables alpha-equivalent comparisons."""
 
     __instances__: dict[tuple["Type", Hashable], "NominalVariable"] = {}