The Palin portrait by Bruce Elliott, 68, is hanging at the Old Town Ale House, described by The Chicago Tribune as a dive bar on the city's North Side frequented by comedians from the nearby Second City Theater.
Elliott told the newspaper he has a bit of a crush on the nominee.
"I've been following her religiously," he said. "I had never heard of her before, like everyone else. I find her bizarrely fascinating, even though I pretty much despise everything she stands for."
Elliott's wife, Tobin Mitchen, owns the Ale House and has added the nude to a collection of more than 200 celebrity portraits and other racy art. The artist told the Tribune he began by painting her smile and trademark glasses, later adding details including a gun, red high heels, polar bear rug and a frightened-looking moose.