I think you mean "..., nicht?" linguist... as for example "Du gehst heute abend auch weg, nich(t)?" It means the same as "...oder?" and is a perfectly valid tag-question ;-) but it is not very usual in Germany, excapt for the Northern parts, I believe...
... where the "t" at the end oftenly isn't pronounced, so this could really be what he's looking for.
