AWD disable light

Well I know that if you have two different size tires on the vehicle that it can throw off ABS and AWD systems, causing general havoc as the ABS and traction control module will see different wheel speeds at the same time. But if you have all four tires the same size, then that is not the issue. I will say that neither size is the proper stock size for that vehicle. Sizes should be either 215/70/R16 or 225/60/R17.

A failed wheel speed sensor could be an issue and could be why they replaced a bearing/hub. If it was a hub assembly (which it probably was) then that would have come with a new sensor.

That light being on indicates that the system has set a diagnostic fault code. You might try unhooking your battery for ten minutes and then hooking it back up. That will clear out any trouble codes and data and give the computer a fresh start. Maybe, just maybe, the light will not come back on. It probably will though. If it does come back, you may have to take it to the Chevrolet dealership in your area and see what codes they can.

Do that and let us know what you find.

AWD can be very fussy. I am skeptical of it being a wheel bearing (if that is the bearing they changed) though. Normally that will also turn on the ABS and brake warnings along with the AWD light as they are the primary users of those sensors and the AWD system piggybacks on them.

I would go to a dealer or shop that has a good scan tool and have them pull the codes from the AWD system. There are a few items that are common failures that will turn that light on but the code(s) would tell you for sure. Most of the issues are in the rear differential, the clutches and actuator that makes the system operate being the bigger issues. The wiring to them also gets corroded and will cause problems.
Knowing the codes would be the first step.