i worked on cars professionally for over 5 years and never hear of having to replace a TPMS sensor with new wheels and tires. Some times I've had to retrain the sensors through the OBD plug-in , on dash computer , or a TPMS magnet. Rare cases we would have to send it to the dealer to get reprogrammed but mainly just on the toyota's.
What I would do is start with the basics check the air pressure ( keep in mind just cuz you filled it with air dosen't mean that its right the TPMS will go off when its to high as well )and take it for a drive i believe the cobalts reset automatically after a few mins of driving if not check the owners manual for the proper rest. If that dosent work take the valve stem caps off and try again.
Has been one or two times the batter has died but the batter normally last around 5 years.
hope this helps
(ps i know that if the stock tpms dosent fit you can buy others that may fit better so maybe thats where you got that change the tpms with the new rims and tires)