Preheat your oven to 350 degrees F.
This creates the perfect environment for your cheesy casserole to bake evenly.
Boil the spaghetti in chicken broth until al dente.
Avoid overcooking to keep its perfect texture.
In a large bowl, combine shredded chicken, cream of mushroom soup, diced tomatoes, bell peppers, onions, salt, and black pepper.
Mix everything thoroughly to blend the flavors together.
Add cooked spaghetti to the mixture.
Stir in half of the cheddar cheese until everything is well mixed.
Transfer the mixture to a greased baking dish.
Sprinkle the remaining cheddar cheese evenly on top.
Bake uncovered for 30 to 35 minutes, or until everything is bubbly and the cheese has melted nicely.