Across their 15-song set, Post Malone touched on all three of Nirvana’s studio albums (including “School” from its debut, “Bleach”) and played all but two of the tracks off the group’s landmark 1991 album “Nevermind.” That they skipped “Smells Like Teen Spirit” speaks again to the purity of the performance’s overall intention — not to pander to easily meme-able, least-common-denominator Nirvana nostalgia but rather to share with a captive audience (here we are now; entertain us) some tunes that he and his buddies just really love playing live.