01 - Preheat your oven to 175°C (350°F) to ensure even baking throughout the casserole.
02 - Strain and rinse the black beans. Dice the red bell pepper and white onion into small, uniform pieces.
03 - In a large mixing bowl, combine the cooked diced chicken, sour cream, lime juice, diced tomatoes, and taco seasoning. Fold in ½ cup of the shredded cheddar cheese.
04 - Spray a 23×33 cm (9×13 inch) casserole dish with cooking spray. Spread the black beans, diced peppers, and diced onions in the bottom. Pour the chicken and sour cream mixture evenly over the vegetable layer.
05 - Sprinkle the remaining cheddar cheese on top and garnish with diced green onions.
06 - Bake for 28-30 minutes until the cheese is bubbly and golden brown.
07 - Serve hot with your choice of toppings such as sour cream, avocado slices, jalapeño slices, tortilla chips, and salsa.