- Cook the spaghetti according to package directions until al dente. 
- Drain it and set aside. 
- In a large skillet over medium heat, sauté onions, mushrooms, and bell pepper until softened. 
- This should take about 5 minutes. 
- Add the can of tomatoes, cream of mushroom soup, chicken broth, salt, black pepper, garlic powder, and onion powder to the skillet. 
- Stir well. 
- Combine the mixture with the cooked chicken and spaghetti. 
- Transfer to a greased baking dish. 
- Sprinkle the shredded cheddar cheese evenly over the top. 
- Bake in a preheated oven at 350°F for 25 minutes or until bubbling. 
- Serve hot!