Begin by breaking the spaghetti into thirds and boiling it in a large pot of salted water. Cook according to package instructions, reducing the cooking time by one minute until it’s al dente. Drain the spaghetti and set it aside, allowing it to cool slightly while you prepare the other ingredients.

While the spaghetti cooks, preheat your oven to 350°F (175°C). This will ensure the oven is properly hot when you’re ready to bake your casserole.

In a large mixing bowl, combine the cooked spaghetti, shredded chicken, cream of mushroom soup, cream of chicken soup, diced orange and green bell peppers, minced onion, and garlic. Fold in the diced pimentos and chicken broth, then sprinkle in cayenne pepper, salt, and pepper to taste.

Grease a 9 x 13-inch casserole dish with cooking spray or a splash of oil. Transfer the chicken and spaghetti mixture into the dish, spreading it evenly.

Sprinkle the grated cheddar cheese over the chicken spaghetti mixture, covering the entire surface.

Place the casserole in the preheated oven and bake for about 30 minutes, until the cheese is melted, bubbly, and slightly golden on top.