I'm not in major disagreement with you about Nas' resume in general, it's why I find the arguments that he should be over Hov disingenuous at best, outright lying at worst...
As it compares to Big, i just think it has to matter that Nas was here and hot before Big, sustained his relevancy while Big was here and on fire, and was hot AFTER Big. Like how and for what reason do we undermine that? It's not like Big's star completely snuffed Nas out...
The quality of Nas' best work holds up with Big's as well. Big was a bonafide hit maker, but Nas is as versatile and creative a lyricist as Big ever was. So even if you give Big the edge in lyricism there us no major gap...
So ultimately for me the guy with more work on the board gets the lead when the quality of the work was otherwise level...
About LL, come on, homie. You know by the time Big hit big LL was already transitioning towards acting (In The House). LL was still dropping classic records while Big was popping (Loungin, Doing It, etc) and this was with his attention pivoting into acting. You can't shyt on LL like Big came and took his star, like you said James was the original rap SUPERSTAR. His combo of songwriting, lyricism, hits, sex appeal, crossover appeal, is the blueprint every rapper including Big could bite from moving forward...
LL was hot for a strong 7 or 8 years before Big was even heard of, don't do this, fam. His longevity as an elite rap star can't be shytted on...
Ultimately I'd be cool with Big over LL because unlike with Nas, LL's lyricism really ain't fukking with Big's, and I do think Big's peak work is stronger than LL's by a notch. But it's only a notch and LL being the OG GOAT, having classic work, being That Guy YEARS before Big's star was born, it's a coin flip...