Place onion, garlic, chicken, chicken broth, beans and chile peppers in crock pot.
Cook for 6-8 hours on low, or 3-4 hours on high.
After cooking, remove chicken breasts from slow cooker and shred meat.
Return meat to slow cooker, and add in cumin, oregano and cayenne pepper. Let cook an additional 15-20 minutes.
Stir in Mexican style cheese blend, stirring until melted.
Serve with an extra sprinkle of cheese, and sour cream if desired.
(If you feel like it needs a little more flavor, add in a seasoning packet of McCormick White Chicken Chili at the end of the day)