diff --git a/lib/Bindings/Python/SupportModule.cpp b/lib/Bindings/Python/SupportModule.cpp
index e32010373985..ed159c5aa554 100644
--- a/lib/Bindings/Python/SupportModule.cpp
+++ b/lib/Bindings/Python/SupportModule.cpp
@@ -28,16 +28,32 @@ void circt::python::populateSupportSubmodule(py::module &m) {
   m.def(
       "_walk_with_filter",
       [](MlirOperation operation, const std::vector<std::string> &opNames,
-         std::function<MlirWalkResult(MlirOperation)> callback,
-         MlirWalkOrder walkOrder) {
+         std::function<py::object(MlirOperation)> callback,
+         py::object walkOrderRaw) {
         struct UserData {
-          std::function<MlirWalkResult(MlirOperation)> callback;
+          std::function<py::object(MlirOperation)> callback;
           bool gotException;
           std::string exceptionWhat;
           py::object exceptionType;
           std::vector<MlirIdentifier> opNames;
         };
 
+        // As we transition from pybind11 to nanobind, the WalkOrder enum and
+        // automatic casting will be defined as a nanobind enum upstream. Do a
+        // manual conversion that works with either pybind11 or nanobind for
+        // now. When we're on nanobind in CIRCT, we can go back to automatic
+        // casting.
+        MlirWalkOrder walkOrder;
+        auto walkOrderRawValue = py::cast<int>(walkOrderRaw.attr("value"));
+        switch (walkOrderRawValue) {
+        case 0:
+          walkOrder = MlirWalkOrder::MlirWalkPreOrder;
+          break;
+        case 1:
+          walkOrder = MlirWalkOrder::MlirWalkPostOrder;
+          break;
+        }
+
         std::vector<MlirIdentifier> opNamesIdentifiers;
         opNamesIdentifiers.reserve(opNames.size());
 
@@ -68,7 +84,27 @@ void circt::python::populateSupportSubmodule(py::module &m) {
             return MlirWalkResult::MlirWalkResultAdvance;
 
           try {
-            return (calleeUserData->callback)(op);
+            // As we transition from pybind11 to nanobind, the WalkResult enum
+            // and automatic casting will be defined as a nanobind enum
+            // upstream. Do a manual conversion that works with either pybind11
+            // or nanobind for now. When we're on nanobind in CIRCT, we can go
+            // back to automatic casting.
+            MlirWalkResult walkResult;
+            auto walkResultRaw = (calleeUserData->callback)(op);
+            auto walkResultRawValue =
+                py::cast<int>(walkResultRaw.attr("value"));
+            switch (walkResultRawValue) {
+            case 0:
+              walkResult = MlirWalkResult::MlirWalkResultAdvance;
+              break;
+            case 1:
+              walkResult = MlirWalkResult::MlirWalkResultInterrupt;
+              break;
+            case 2:
+              walkResult = MlirWalkResult::MlirWalkResultSkip;
+              break;
+            }
+            return walkResult;
           } catch (py::error_already_set &e) {
             calleeUserData->gotException = true;
             calleeUserData->exceptionWhat = e.what();