Preheat the oven to 350°F (175°C).
In a large bowl, combine 2 cups of shredded cooked chicken, 1 large diced red bell pepper, 1/2 diced red onion, 1/2 cup sour cream, 1/2 cup jalapeno-flavored cream cheese, 1 teaspoon taco seasoning mix, and 1/2 teaspoon salt.
In a separate bowl, mix 1 can of rinsed and drained black beans, 1/4 cup hot water, and 1 tablespoon ground cumin. Roughly mash with a fork until evenly mixed.
Layer 3 flour tortillas into the bottom of a 9x9-inch baking dish.
Top tortillas with 1/2 of the salsa from 1 jar, 1/2 of the black bean mixture, and 1/2 of the chicken mixture.
Repeat layering with the remaining ingredients, ending with the chicken mixture.
Sprinkle the casserole with 1/2 cup shredded mozzarella cheese.
Bake in the preheated oven until the top is golden, about 30 to 35 minutes.
Let the dish stand for 5 minutes before serving.