Cook the pasta according to package directions. Drain and set aside.
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Cook the onions, garlic, and green peppers for 5-6 minutes until softened.
Add the chicken broth, cream of chicken, and Rotel tomatoes (with the juice). Bring to a boil, then reduce to a gentle simmer for 2-3 minutes.
Make sure the heat is very low as you stir in the cheddar, mozzarella, and chicken breast. Cook until the cheese melts, then season with salt and pepper to taste.
Remove from the heat. Add the cooked spaghetti to the pan and toss everything together until the pasta is coated with the sauce. Enjoy!
Nutrition information is calculated using an ingredient database and should be considered an estimate.