Cook turkey, celery, and onion in a skillet over medium heat until turkey is no longer pink, 5 to 7 minutes. Add chili powder, black pepper, cumin, and red pepper. Cook and stir for 2 minutes. Stir in tomato sauce, chili beans, and cannellini beans. Cook until heated through, about 5 minutes. Set aside.

Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking pan.

Combine cornbread mixes, milk, and egg in a bowl and mix well. Spoon batter into the prepared baking pan. Spoon turkey mixture over batter.

Bake in the preheated oven, uncovered, until edges of cornbread are nicely browned and center appears to be set, about 20 minutes. Remove from oven and sprinkle Cheddar cheese on top. Return to the hot oven and bake until cheese is melted, 5 to 10 minutes more.