Fold the cooked noodles into the mixture, gently tossing until the noodles are well coated.
Transfer the mixture to a greased 9×13-inch baking dish, spreading it into an even layer. Sprinkle the remaining 1/2 cup shredded cheddar cheese evenly over the top.
To make ahead: Cover the dish tightly with foil and refrigerate for up to 24 hours.
When ready to bake, preheat the oven to 350°F (175°C). If the casserole has been chilled, remove it from the fridge while the oven heats.
Bake, covered with foil, for 20 minutes. Remove the foil and continue baking for another 15–20 minutes, or until the casserole is bubbly around the edges and the cheese on top is melted and lightly golden.
Let the casserole rest for about 5–10 minutes before serving so it can set up a bit and is easier to scoop.
Serve warm, straight from the pan, and enjoy with your favorite simple sides.
For picky eaters, you can swap the cream of chicken soup for cream of mushroom or cream of celery if that’s what they’re used to, or use a mild shredded cheese like Colby Jack instead of sharp cheddar. If you have a veggie-loving crowd, stir in 1–2 cups of frozen peas and carrots or mixed vegetables before baking (this does add an extra ingredient, so you can also just serve veggies on the side if you want to keep the main dish strictly 5 ingredients). For a little crunch, top the casserole with crushed butter crackers or plain potato chips mixed with a tablespoon of melted butter before baking uncovered for the last 10–15 minutes. To stretch the recipe for a larger group, serve it over rice or mashed potatoes, or add an extra handful of noodles and a splash of milk to loosen the mixture. You can also make this with leftover turkey instead of chicken after a holiday meal. If you’re taking it to a church supper, bake it at home until just bubbly, then keep it warm in an insulated carrier; give it a quick reheat, uncovered, in the church kitchen if needed to refresh the cheese on top.