Wu.
Saying otherwise is borderline crazy to me and tells me that the person wasn't actually around back then.
The earliest Wu was slightly before my time, but I was almost in high school when Forever dropped. It's hard to explain how big that time was. People wore Wu Wear clothing, everyone had the fukking Wu bird logo drawn onto their notebooks at school, everyone debated on who the best member was, and everyone could rap the whole Triumph song from front to back, and Wu was just generally a cultural phenomenon that was bigger than music. Even non rap fans would rap Deck's opening verse on Triumph. Triumph at the time was maybe only the 2nd or 3rd million dollar music video ever made. I mean c'mon...Wu took a 6 minute track of nothing but bars and made it a single with a million dollar music video out of it...who else has done that?
I never remember Nas being disliked, and If I Ruled the World was a big song the year prior, but the earth wasn't moving for Nas. Nas at his peak of popularity was probably Ether, and he was the king of hip-hop, but Wu was bigger than hip-hop in '97 and was arguably a pop act. No disrespect to Nas as he's in my top 5 dead or alive.
I remember Only Built For Cuban Linx and Liquid Swords dropped in '95 within a few months of each other. That Purple Tape and Liquid Swords time is when the hype started getting crazy and that lead up to Forever dropping was an insane time in terms of hype.
I dont think yall understand the love that white people have/had for wu tang. Wu was way bigger during their peak than Nas
All cultures, honestly. People in Asia were also crazy for the Wu. Like I said, Wu-Tang in '97 was one of the biggest things in all of pop culture. For a moment they were bigger than hip-hop, and when OP asked who was bigger at their peak, it's hard to top anyone that was bigger than hip-hop. Nas during the Ether time in '01 was HUGE, but it wasn't a worldwide event in the way that Forever was in '97.