OK, I'm cheating a little bit with this one, because "You Know You're Right" is obviously an archival song from the 90's - allegedly, the last song Kurt Cobain worked on, possibly intended for the next Nirvana album if such was going to happen. However, it was allowed as it didn't see official release until 2002.
Honestly, listening to "You Know You're Right"... I think for the next LP, Nirvana could've actually bettered In Utero. It's one of the most raw and heavy things they ever recorded, a bitter reflection on emotional manipulation and being demonised, surrounded by vicious In Utero style feedback but with a massive chorus that would have fit in well on the poppier Nevermind. And it has what I think is one of Kurt's greatest vocal performances, ever. It's a goddamn tragic song, is what it is - the good die young, they say. Just makes me wonder what might have been - but for everyone in 2002, when grunge was the day before yesterday's news, it was a powerful reminder of why Nirvana mattered in the first place rather than just being a name on a T-shirt.