Galaxymans 4.9.2_NVIDIA_Techs branch packages fine for me, and I had trouble with the NVIDIA branches not packaging before switching to it.
The only unclear thing for me (being new) from the steps on GitHub was that I also needed set my configuration set to ‘Development’ rather than ‘Development Editor’ after step 5 and then building ‘UE4’ again.
is to generate UE4Game.exe which apparently is a necessary step to get packaging working.
Make sure to switch back to ‘Development Editor’ before launching with debug.