That's somewhat contrary to the Navisworks development cycle. Previously they had an NWD and NWC exporter plug-in for AutoCAD. NWD publishing was subsequently restricted to natively inside the programs (Simulate, Manage) while the NWC exporters are now free to use i.e. they don't require a license or install of the parent program. I don't think they're going to reverse that any time soon.
I have to ask - why is it "very necessary" to export NWD directly from Revit? Simulate and Manage are included as part of the Suite and Collection licenses. Not only can they publish in-program but they can also be scripted via command line.