Is Nirvana post-punk?

Might seem like an odd band to view as post-punk, but wikipedia lists Nevermind as a post-punk album, and I personally have always heard a very strong post-punk influence in their murky, moody, haunting sound. Something in the Way, Francis Farmer, Big Long Now, All Apologies, Heart-Shaped Box, and a few others have a very post-punk sound. So would you say the band fits this label in any way?