Put the chicken in a slow cooker. Sprinkle on the chili powder, cumin and some salt and pepper. Add the tomatoes, chicken broth, black beans, tomatoes with chiles, tomato paste, onion, chipotle pepper and red and yellow peppers. Stir, place the lid on the slow cooker and cook for 5 hours on high or 8 hours on low.
Stir in the lime juice. Remove the chicken to a plate and use 2 forks to break it into chunks (or shred it finely). Return the chicken to the pot, taste and add more seasoning if necessary.
Serve piping hot in a bowl with avocado, sour cream, grated cheese, crushed tortilla chips and cilantro leaves on top!