Before You Begin:
Prepare your cookware as needed. Cooking times and results may vary depending on your equipment and ingredients.
Preheat Oven
Heat oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
Cook the Noodles
Bring a pot of water to a boil. Cook noodles according to package directions until al dente, meaning tender but still slightly firm. Drain thoroughly to remove excess moisture.
Prepare Sauce
In a large bowl, whisk soup, milk, garlic powder, onion powder, salt, and pepper until smooth.
Combine Filling
Add cooked chicken, drained noodles, cheese, vegetables, celery, and onion. Stir gently until evenly coated.
Transfer to Dish
Spread mixture evenly into prepared baking dish.
Add Topping
Mix breadcrumbs and melted butter. Sprinkle evenly over casserole. Add extra cheese if desired.
Bake
Bake for about 25–30 minutes, or until the topping appears lightly golden, the edges are bubbling, and the center is hot throughout. Cooking time may vary depending on oven performance.
Rest Before Serving
Let stand 5–10 minutes so the sauce thickens slightly and portions hold together.