I installed Atom and Nuclide and opened a newly initialized React Native Project in Atom. Once I try to start the React Native Packager I am getting an error stating
An unexpected error occurred while running the React Native Packager process: ENOTDIR: not a directory, stat '/Users/UserName/Documents/MyProjectDirectory/ProjectName/package.json/package.json'
There is no directory called package.json and I'm not aware how this path could have become corrupted. Any help would be much appreciated.

Not a solution, but a workaround for now:
Or, generally, running
react-native run-ios(orrun-android) will start the packager as a matter of course (in a separate terminal window).(Also no clue why this is happening; for me, it was after the upgrade from RN
0.49~>0.50.)