If I have a layover in Chicago, could I get arrested for having a firearm in my checked baggage?

People do not get arrested for having a properly licensed and packed firearm in their checked bag. It must be registered with the airline when you check in, and then you will be fine You don't have access to your checked bag at your layover site.

EDIT: If you miss your flight or it is canceled, you will be put on a later flight. You still won't have access to your bag. If they do, for whatever reason, give you your bag, then you still should not have any trouble assuming all of your paperwork is in order.

Your checked bag will merely be transferred from one plane to the next, not going through any inspection. You will not have physical possession in Chicago. I don't see how Illinois could know what is in your suitcase.

No. HOWEVER, you must declare that you have a firearm when you check in. This will ensure that your bag is properly secured during the transfer

It has happed before, even when properly licensed, declared with TSA, and properly packed firearm in their checked bag. A hunter was returning from an African hunt, when he arrived in NYC, he found is connecting flight had been concealed. There he stood in the middle of liberal gun control heaven, with 5 firearms, because of no fault of his own, and the police were called. That begin a nightmare he would very much like to forget.

Chicago is even more strict than NYC on gun control, and they hate anyone with a firearm, even their own police. If you don't take possession of your luggage, you should be okay, but if you have to go through Customs, you will have to take possession of your luggage, then you are in control of the firearm, and all bets are off in that liberal gun control bigot run cesspool.

You bring a gun in your bag you better have all the correct forms filled out

No, because you will not have access to the checked bag.