Homemade Chicken Spaghetti

Name: Homemade Chicken Spaghetti
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Cuisine: Italian, American
Ingredients: 8 ounces spaghetti; 2 cups cooked shredded chicken; 14 ounces canned diced tomatoes with chilies (such as Rotel, or petite diced tomatoes, lightly drained); ¼ cup salted butter; 1 medium yellow onion (chopped); 1 clove garlic (minced); ½ green bell pepper (chopped); ¼ cup all-purpose flour; 1 teaspoon Italian seasoning; 1 cup chicken broth; 1 cup half and half (or light cream); ½ cup shredded Parmesan cheese; 2 cups shredded sharp cheddar cheese (divided); ¼ teaspoon salt (more to taste); ¼ teaspoon black pepper (more to taste)