When Domenic “Nicky” Palermo signs onto Zoom from a stopover at Connecticut’s Mohegan Sun casino and hotel, his fatigue is quickly audible. The Nothing frontman is taking a break in between unloading excess merch from the band’s recent tour run while simultaneously trying to shepherd the largest edition yet of Slide Away , the steadily rising festival he accidentally — and somewhat improbably — turned into one of underground rock’s most vital annual gatherings. “I dare say I bit off a little bit more than I can chew,” the bearded Palermo says with a laugh. That may be true on paper. This year’s Slide Away sprawls across six shows in three cities — Brooklyn Paramount on Friday and Saturday (May 15-16), Chicago’s Aragon Ballroom on May 22-23 and Los Angeles’ Hollywood Palladium on May 29-30 — with roughly 20,000 tickets sold in total. Nothing will perform at all three stops in support of its deeply personal new album, A Short History of Decay , released in February.…