The new “Sketch Checker” in NX2412 is rather nice. (It might be that some other CAD systems already have something like this, I don’t know.)
You can configure what types of things should be flagged (tiny objects, overlapping objects, almost-tangents, etc.) and then you get the flags:
NX2412_chk1.jpg
You right-click on a flag, then you get the options dialog:
and the corrections all have worked fine so far.