Place all the ingredients except sour cream into your slow cooker. Cook on high for 3-4 hours.
Remove chicken breasts and shred. Return to pot and stir well. Add sour cream and stir to combine.
Serve with cheese and tortilla chips!
Press saute on the Instant Pot. Add onion and garlic and sauté until soft, about 3-4 minutes.
Add remainder of ingredients to the pot, except chicken and sour cream. Stir well.
Place chicken breasts on top of mixed ingredients.
Secure the lid, and make sure the lever on top is switched to 'sealed'.
Cook on high pressure for 20 minutes. Quick release.
Remove chicken and shred with two forks. Add chicken back into the soup, stir and add salt and pepper to taste.
Stir in sour cream and serve soup warm.
Add additional toppings as desired: Sliced avocado, tortilla strips, fresh cilantro.