A chirping noise is coming from my AC unit. I think it is coming from the fan motor. The squeaky chirping noise (sounds like a cricket) kind on cycles so that during a cooling cycle, the fan will go from making no unusual noise to this squeaky chirping noise and then back to no noise again. Do you think it is a motor bearing going out? If not, then what else could it be? Is this likely something I can repair myself, or do I need a professionals touch?

Some motors are meant to have oil or grease added. Look for a little thing sticking out from where the bearing is. If it has a flat, hinged cap, add a few drops of a light machine oil. If it is more Coke bottle shaped, it is a Zerk grease fitting. A couple of pumps with a grease gun is all it should need. Many of the bearing are sealed, lifetime bearings. When it goes dry, the motor's life is ended. A bearing transplant might save it. That is a challenging project for DIY. You might be able to remove the motor and take it to a motor shop and let them use their specialized tools to replace the bearing.

If the fan is belt driven, it could be the bearings in the fan shaft, or even the belt itself. A good shot of belt dressing from a spray can might fix the problem.