I don't think there's a Chase ATM in the secure area of ORD - I know there's a BOFA and Harris Bank, for sure. But there definitely used to be one at the airport CTA station, just outside the fare gates (IIRC, if you're walking down from T1, it should be at the wall on the far end of the turnstyles...so should see it roughly straight ahead if you are walking from the United terminal). I presume its still there, though didn't notice (though wasn't looking, either), when I was walking by the area around Thanksgiving.