I think it's awkward that you, as someone who wasn't around for the original release of either of these albums, would asking this question.
they aren't in the same category.
Ten was amazing and Nevermind was awesome.
Growing up in the early 90s was a great time to be a music lover. no one would have ever compared these albums back then because they are two completely different styles of albums but still in the same genre.
Blood Sugar Sex Magic by Red Hot Chilli Peppers and Vasaline by STP were also big albums of the time. Sugar Cubes, Crash Test Dummies, Fugazi, Crowded House and soooo many other bands defined the Quasi pop underground era and early MTV generation.
Just like today, you can't compare bands that sound nothing alike.
the music was different but the feeling was the same. Pearl Jam was more like a sad night at home with some wine and a joint. Nirvana was the feeling of being trapped and rebeling through the walls with your fists and teen angst.