For my fellow Guppy FOs, the last two times I went into Chicago in wintery conditions my Captains briefed the ILS to 9R or 9L per the ATIS. I inquired about braking action and runway condition at turn off, and after the suggestion of a longer runway both agreed that 10C was a better choice in the conditions. It made for a much longer taxi in, which wasn't ideal, but on one of the two occasions, the slippery turn off on 10C made my Captain say, "Wow! Glad we changed to the long runway."
Your Captain has more experience, but they will listen to your input. Don't be afraid to suggest a more conservative action if you think its appropriate. You're going for the same ride they are!