Place chicken breasts in the bottom of your slow cookerAdd chili powder, onion powder, cumin, garlic powder and cayenneTop with beans, corn, chiles and finally, the chicken stockCook on low for 5 - 7 hoursRemove the chicken from the slow cooker and shred the chicken using 2 forks. Return the chicken to your slow cooker.In a non-stick skillet, melt the butter. Sprinkle the flour over the butter and whisk to completely blend. Allow the butter/flour mixture to cook until is starts to brown. Slowly whisk in the milk and boullion, making sure all lumps are gone.Allow this mixture to cook for about 5 minutes or until it starts to thicken.Add the butter/flour/milk mixture to the crockpot and stir to combineAdd the sour cream.Cook for another hour on low and serve!