A reverse ‘no true Scotsman’ could mean different things. If by it you mean an ‘all true Scotsmen’ argument, then that is a sweeping statement or overconfident generalisation.

It’s actually the same fallacy, because ‘no true x does y’ is the same as saying ‘all true x does not-y’.

If you mean ‘only a true Scotsman would’, it’s really the same again.