As long as there's no snowstorm, which Chicago is famous for this time of the year, you should have plenty of time to go to MDW airport to catch your flight. When family was still living in Chicago, I would visit them 2-3x a year and one time, there was a snowstorm in the area so my flight got delayed for 7hrs and then we got stuck at the runway after landing for almost an hour waiting for an available gate for the plane to dock.
Cheers and best of luck on this day.