I'm unsure which question you are asking: (1) Are there other nirvanna records that sound like their unplugged album
or (2) other artists who sound like nirvanna unplugged? Maybe you are interested in both, so:
(1) Some of the songs on the unplugged album are on their first two albums in "plugged" versions. If you don't have "Bleach", their first album, it wouldn't be a bad purchase and, I think, is slightly better than "Nevermind". Anyway, I think Nirvanna displays a consistent sensibility soundwise and if you like the unplugged stuff (which I think is some of their best recorded stuff) you'll probably like their other stuff. Don't be put off by the huge pop success of "Nevermind".
(2) On the unplugged album Nirvanna covers songs by Leadbelly, the Meat Puppets, David Bowie, and, i think, the Vaselines (I'm not sure about the Vaselines on the uplugged album--I know they covered them elsewhere). So, you could check those guys out as well.
Well, this is just off the top of my head. If you'd like, I'll think about it some and respond again later.
take care.