Preheat your oven to 350°F (175°C).

Strain and rinse the black beans, then finely dice the white onion and red bell pepper.

In a large mixing bowl, combine the cooked, diced chicken, sour cream, lime juice, and diced tomatoes. Stir in taco seasoning and fold in ½ cup of cheddar cheese.

Spray casserole dish with cooking spray. Layer the black beans, diced peppers, and onions, then spoon the chicken mixture over and top with remaining cheddar cheese.

Bake for 28-30 minutes until cheese is bubbly and golden brown.

Let the casserole rest for 5 minutes, then garnish with sour cream, sliced avocado, and jalapeños.