First, preheat the oven to 350 degrees Fahrenheit. Grease a 9-inch by 13-inch baking pan and set aside.
Cook the spaghetti noodles according to the package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the cooked chicken, cream of mushroom soup, cream of chicken soup, sour cream, broth, diced onion, diced bell pepper, diced celery, garlic, Italian seasoning, paprika, salt, and pepper. Mix together.
Add the cooked noodles to the chicken mixture. Add in 1 cup of the cheddar cheese. Stir until well combined.
Transfer the mixture to the greased baking pan. Spread into an even layer.
Then, sprinkle the remaining 1 cup of cheddar cheese on top of the casserole.
Bake in the preheated oven for 25 to 28 minutes, until the casserole is hot and bubbly.
Finally, remove it from the oven. Garnish with chopped parsley if desired. Serve!
