In a 3½ to 5 quart slow cooker, combine drained beans, tomatoes, corn, onion, and bell pepper. Place 2 chicken breasts on top of mixture. In a large bowl, whisk together enchilada sauce and soup. Gradually whisk in milk until smooth. Pour sauce mixture over ingredients in cooker.Cover; cook on low heat for 6 to 8 hours or on high for 3 to 4 hours.
Remove chicken and cut or shred into bite sized pieces. Add chicken back into soup.
Top with pepper jack cheese and serve. Can also be topped with avocado, sour cream, or crushed tortilla chips. Note: if the soup is too thick for you, just add a little more milk after it’s all cooked.