Absolutely easy choice. Was grunge even a thing after 1995? I still listen to Appetite Lies and Illusion, haven't heard a Nirvana song in maybe ten years
Was GNR even a thing after 1991? No, because Nirvana killed them ded.
GnR resuscitated hard rock when it was on life support after being pussified by hair/glam bullshit. Nirvana headed the grunge movement. Both were flavors of the month that lasted a couple years. GnR stands the test of time for me; Nirvana, not at all. Nirvana didn't kill GnR; they did it to themselves, just like Kurt
And Styx sucks
And GnR did a damn good job of it. I still listen to Appetite regularly. Still, Nirvana wasn't just the leader of the grunge pack, rather, they made alternative the mainstream style of the 90s, which was a YUGE deal. Hell, even by '93 GnR was doing an album of punk covers, which is a testament to Nirvana's influence.