502 bad gateway is the error that nginx returns when NodeBB isn't running. Try running NodeBB will ./nodebb slog or ./nodebb dev and look for errors. Odds are that it is encountering an error and dying.
@JaredBusch NodeBB should work on Node 4+... just fyi 😄
Oh, I have a perfectly working instance that I have been using for over a year. the problem is I can not spin up a new instance in a new VM to save my life.
I know for a fact that it is not this damned hard.
At this point I can only assume I have missed a step or something.