Cook the spaghetti noodles according to the package instructions until al dente. Drain and set aside.
Preheat your oven to 350°F (175°C).
If you haven’t already cooked the chicken, poach or grill it until fully cooked. Once cooked, shred or dice the chicken into bite-sized pieces.
In a large skillet or saucepan, heat the olive oil over medium heat. Add the diced onion, bell pepper, and minced garlic. Sauté for about 5-7 minutes, or until the vegetables are softened.
Stir in the cream of mushroom soup, cream of chicken soup, and chicken broth into the skillet with the sautéed vegetables. Mix well until smooth and combined. Add the dried oregano, dried basil, salt, and pepper. Let the sauce simmer for a few minutes to allow the flavors to meld together.
Add the cooked chicken, cooked spaghetti noodles, shredded cheddar cheese, and shredded mozzarella cheese to the skillet with the sauce. Stir until everything is well coated and evenly combined.
Transfer the mixture to a greased 9×13-inch baking dish. Sprinkle some extra cheese on top if desired. Cover the baking dish with aluminum foil and bake in the preheated oven for 25-30 minutes, or until the cheese is melted and the dish is heated through.