Combine all ingredients except flour and milk into a 6-quart slow cooker; stir to combine. Cover and cook on low for 4 hours.
Remove chicken; shred and place in the refrigerator.
Whisk together flour and milk in a small bowl; pour into chili and stir to combine.
Cover; cook on high for 30 minutes, stir shredded chicken back into chili, and serve with toppings. Taste before adding any more salt & pepper.
