Preheat oven to 350°F. Spray a 2-quart baking dish (about 8 or 9-inch square) with cooking spray and set aside.
In a large bowl, combine cornbread, green bell pepper, onion, celery, and cheese.
Place half of the cornbread mixture in the prepared baking dish. Spread chicken in an even layer over the cornbread mixture.
Whisk together soup and broth until completely combined. Pour soup mixture over the chicken. Spread remaining cornbread mixture over the chicken and gently press down to form a top crust.
Bake, uncovered, for about 30 minutes, or until hot, bubbly, and golden brown on top.
Notes
The veggies stay crisp-tender in the casserole. If you prefer softer vegetables in your finished dish, sauté them in olive oil before stirring them into the casserole.
Use day-old (stale) cornbread for the best results. If you don't have leftover cornbread on hand, you can purchase a tray of cornbread at the grocery store, or bake your own cornbread at home.
To achieve this perfectly dried out cornbread, let the cubed cornbread sit in an open, zip-top bag or bowl on the counter for at least 24 hours.
If you don’t have time to wait for your cornbread to dry out on its own, you can toast fresh cornbread in the oven. To do so, arrange the cubed cornbread on rimmed baking sheets. Bake in a 275°F oven for about 30-40 minutes, tossing occasionally. Let the cornbread cool and dry before using in the recipe.
This casserole uses very simple ingredients. If you prefer more seasoning, feel free to add fresh herbs like sage, thyme, rosemary, or parsley; spices like poultry seasoning, seasoned salt, garlic powder, onion powder, or cayenne pepper; or try jalapenos, green chiles, or just some kosher salt and ground black pepper.