Preheat the oven to 350°. Lightly spray a 13x9-inch baking dish with cooking spray.
Cook the spaghetti according to the package instructions. Drain, rinse with cool water and set aside in a large bowl or back in the same pot.
In a medium saucepan over medium heat, add the tomatoes, cream of mushroom, cream cheese, bell pepper, onion, garlic powder, and onion powder. Cook, stirring occasionally, until cream cheese is melted and fully incorporated into the sauce. Pour mixture over the spaghetti, tossing to coat. Fold in the chicken and 1½ cups cheese. Season with salt and pepper to taste.
Transfer the spaghetti mixture into the prepared baking dish and sprinkle with the remaining ½ cup of cheese. Cover loosely with foil.
Bake for 30 to 35 minutes or until the mixture is bubbling. Uncover and turn the oven to Broil. Broil until the cheese is bubbling and just starting to brown, about 2 to 3 minutes. Let cool for 10 minutes before serving.
Notes
Try to use low-sodium or no-salt-added chicken broth if you’re able to. This allows you to have more control over how salty you’d like the spaghetti and chicken bake to be.
Use the hot version of Rotel for a spicier spaghetti bake.
To easily shred your own cheese, run it through a cheese grater or a food processor’s grater attachment.
Avoid overcooking the pasta as it will turn mushy if cooked for too long.
When adding cheese to the top of the dish, cover all of the exposed spaghetti noodles, so they don’t harden while in the oven.
You can quickly make shredded chicken breasts by poaching them. Simply add chicken breasts to a pot of cold water, bring the water to a gentle simmer over medium heat, lower the heat, cover the pot, and simmer for 10 minutes.
Allowing the chicken spaghetti casserole to cool before cutting gives it time to set up, so the cheese doesn’t slide off when you scoop out a serving.