Komuflage
Insider
Well, either when u chose to create a new world instance, u can chose difficulty, (And some difficulty only suits character of a certain "lvl" kinda how it was done in older Arpgs) or, once u complete the main plot, you unlock NG+ and can chose it when creating a new world instance.One thing we haven't addressed is that there likely won't be an win state to the game that would result in a ng+. What I mean is, what differentiates a ng from a ng+ and how would one decide if it should be a ng or a ng+ as there are no completion parameters.
If u finish the plot in NG+, u unlock NG++/NG2, and so on.