In a 3-1/2 to 5-quart slow cooker combine black beans, tomatoes, frozen corn, onion, sweet pepper, and jalapeño pepper.
In a large mixing 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 setting for 6 to 8 hours or on high-heat setting for 3 to 4 hours.
Stir in Monterey Jack and cheddar cheese until melted.
Ladle into bowls.
If desired, top each serving with sour cream, guacamole and tortilla chips.