1. 1. Preheat Your Oven and Prepare Your Dish: Start by preheating your oven to 375 F (190 C). While the oven heats, lightly grease a 9×13-inch baking dish with cooking spray. This prevents sticking and makes cleanup easier.

2. 2. Combine the Creamy Base: In a large mixing bowl, combine the condensed cream of chicken soup, condensed cream of mushroom soup, chicken broth, milk, black pepper, and garlic powder. Whisk these ingredients together until they are smooth and well combined. This creates the flavorful, creamy sauce for your casserole.

3. 3. Add Chicken and Rice: Stir in the cooked shredded or cubed chicken and the uncooked instant white rice into the soup mixture. Make sure the chicken and rice are evenly distributed throughout the creamy sauce. The instant rice will absorb the liquid as it bakes, becoming tender and fluffy.

4. 4. Fold in the Vegetables: Gently fold in the thawed frozen mixed vegetables. You want them evenly distributed so every spoonful gets a colorful, nutritious boost. Thawing them briefly helps them cook through evenly in the casserole.

5. 5. Assemble and Bake: Pour the entire mixture into your prepared 9×13-inch baking dish, spreading it out evenly with a spatula. Cover the dish tightly with aluminum foil. This helps to steam the rice and keep the casserole moist during baking. Place the dish in the preheated oven and bake for 20 minutes.

6. 6. Add Cheese (Optional) and Finish Baking: After 20 minutes, carefully remove the foil. If you’re adding cheese, sprinkle the shredded cheddar evenly over the top of the casserole. Return the uncovered dish to the oven and bake for another 5-10 minutes, or until the cheese is melted and bubbly, and the casserole is heated through and lightly browned on top. The rice should be tender and all the liquid absorbed.

7. 7. Rest and Serve: Once out of the oven, let the casserole rest for 5 minutes before serving. This allows the flavors to meld and the casserole to set slightly, making it easier to scoop. Serve hot and enjoy!