In a large slow cooker, add the chicken breasts and both enchilada sauces. Cook for several 2 to 3 hours on high or 4 to 5 hours on low, or until the chicken is cooked and shreds easily. Remove chicken, shred and return to crockpot.
Add all the remaining soup ingredients, except the sour cream and cook for 1 more hour or until heated through.
Whisk in the sour cream and turn off the heat.
Garnish with tortilla strips, sour cream, and cheddar cheese.