Assuming this is a PVT operation in controlled airspace, so long as it has 1 VOR/ILS, DME, Marker receiver and the GNS430 there are no problems.
Marker receiver is required when its not an ILS/DME approach, such is the case here.
The GNS430 can be used as GPS/RNAV equipment and therefore provide the fix at the NDB.
So to answer the question, the ADF is not required.