While he might best be known as the award-winning producer of Taylor Swift’s first five albums, Nathan Chapman is also a not-so-secret songwriting weapon. He earned his first big hit with Darius Rucker’s lusty twanger “Homegrown Honey,” but he doesn’t limit himself to country, crafting swooning pop (Kesha’s “Godzilla”), swinging blue-eyed soul (Michael Bublé’s “Baby I’ll Wait”), and rousing dance jams (Avicii’s “You Be Love”), too.