Preheat your oven to 350°F (175°C). Lightly grease your 9x13 inch casserole dish with butter or non-stick spray to prevent sticking.
In a large mixing bowl, combine the sour cream, cream cheese, and cottage cheese. Stir until smooth and well blended. Add the two cans of cream of chicken soup, onion powder, and garlic powder. Mix thoroughly until you have a creamy, flavorful sauce.
Fold the chopped cooked chicken into the creamy mixture, ensuring the chicken is evenly coated. This mixture forms the hearty base of your Yum Yum Million Dollar Chicken Casserole.
Pour the chicken and creamy mixture into your prepared casserole dish and spread it out evenly.
In a separate bowl, combine the uncooked cornbread stuffing mix with the chicken broth and melted butter. Stir until the stuffing is evenly moistened.
Sprinkle the prepared cornbread stuffing evenly over the top of the chicken mixture. This will bake into a golden, crispy crust that contrasts beautifully with the creamy interior.
Place the casserole in the preheated oven and bake for 45-50 minutes or until the top is golden brown and the casserole is bubbling around the edges.
Remove the casserole from the oven and let it rest for about 10 minutes before serving. This helps the layers set for easier slicing and serving.