1. Add the diced onion and bell pepper to the bottom of a 5 to 6 quart slow cooker.

2. Pour in the red enchilada sauce and the drained diced tomatoes with green chiles, then stir to combine.

3. Stir in the black beans, frozen corn, chili powder, ground cumin, garlic powder, smoked paprika, salt, and black pepper until everything is evenly mixed.

4. Nestle the boneless skinless chicken breasts into the sauce mixture, turning them once so they are coated and mostly submerged.

5. Cover the slow cooker and cook on LOW for 4 to 6 hours or on HIGH for 2 to 3 hours, until the chicken is tender and easily shreds with a fork.

6. Transfer the cooked chicken breasts to a cutting board and shred them into bite sized pieces using two forks.

7. Return the shredded chicken to the slow cooker and stir it back into the sauce, beans, and vegetables until well combined.

8. Slice the corn tortillas into short strips and gently fold them into the chicken mixture so they are evenly distributed and coated in sauce.

9. Spread the mixture into an even layer in the slow cooker, then sprinkle the shredded Mexican blend cheese evenly over the top.

10. Cover and cook on HIGH for 15 to 20 minutes, until the cheese is fully melted and the casserole is hot and bubbly around the edges.

11. Scoop the casserole into bowls or onto plates and top each serving with sour cream, chopped fresh cilantro, diced tomato, diced avocado, and a squeeze of lime juice.

12. Serve warm and store any leftovers in an airtight container in the refrigerator for up to 4 days.