Why does Nevermind receive so much praise?

Because it was one of the most successful breakthough alternative rock albums. I would compare it to Never Mind the Bollocks, Here's the Sex Pistols; though not extraordinarily good or original, like Nevermind it was at the forefront of its style's breakthough in the mainstream. It's not so much the quality of its content musical content as it is the pop culture context and zeitgeist of sorts which it represents. I believe it was successful because it was different enough to be remembered yet also accessible to the mainstream audiences. To people who had never heard this sort of alternative music before, it was something new. It was essentially a punk band playing pop songs. I really don't see the point in comparing it to Ziggy Stardust and The Spiders From Mars, as Nevermind was essentially a straight-up pop/rock album, whereas Ziggy Stardust was theatrical rock with more eclectic influences.