Creamy Chicken Spaghetti Casserole is a cozy, family-friendly pasta bake made with tender chicken, a rich homemade cheese sauce, and mild tomatoes—perfect for an easy weeknight dinner.
Creamy Spaghetti Casserole with Chicken Breasts
This creamy chicken spaghetti casserole keeps things simple while still delivering big comfort food flavor. You cook the chicken and onions, then make the cheese sauce right in the same skillet—less mess, fewer dishes, and everything builds flavor as you go. The homemade cheese sauce makes it extra rich and satisfying without relying on canned soup, sour cream, or mayo, and mild diced tomatoes keep it kid-friendly without any heat.
Everything comes together easily in one dish, making it ideal for busy weeknights when you don’t want a complicated dinner. It’s the kind of meal everyone actually eats (mine cleaned their bowls…). If you’re in the mood for something similar with beef instead, check out my Baked Spaghetti Casserole with Ground Beef for another easy, family-friendly option.
Ingredients and Cooking Tips
- Chicken (breasts or thighs). Both work well here—breasts are leaner, thighs are a little juicier. Just cut into bite-size pieces so they cook quickly and stay tender.
- Spaghetti. Spaghetti is the base of this casserole and what makes it feel like true comfort food. Cook it just until al dente so it doesn’t get mushy while baking. The noodles on top get slightly crispy in the oven, which adds the best texture contrast against the creamy cheese sauce underneath.
- Diced tomatoes. This is not a spicy casserole by default. Plain diced tomatoes or “Mild” Rotel keep it very kid-friendly. The creamy cheese sauce balances everything out for a smooth, comforting flavor. If you want a little heat, swap in Rotel with green chilies.
- Cheddar cheese. A whole package of shredded cheddar melts into the sauce for that rich, creamy texture. I like using a white + orange blend for extra flavor, but any cheddar works.
- One-skillet base. Cooking the chicken, then building the cheese sauce in the same skillet keeps things simple and adds flavor while cutting down on dishes. Everything comes together fast and easy before baking.
How to Make Chicken Spaghetti Casserole
Cook spaghetti until just al dente, drain, and add it to a greased 9×13 baking dish.
Season chicken with salt and pepper. Cook chicken with diced onion in a skillet until the chicken is cooked through and the onion is soft. Pour this mixture over the spaghetti.
Add the can of diced tomatoes on top. I don’t drain these and welcome the extra juices they provide.
In the same skillet, melt butter. Whisk in flour and cook for about 1 minute until smooth. Add garlic and cook for 30 seconds. Slowly whisk in milk and chicken broth. Cook until the sauce thickens. Stir in 1 1/2 cups of cheddar cheese until melted and smooth. Season with salt, pepper, and paprika.
Pour the cheese sauce over the chicken and spaghetti and mix everything together.
Top with remaining cheddar cheese.
Bake until bubbly and lightly golden on top. I like to let it cook until a couple pieces of spaghetti get nice and crispy!
Let rest a few minutes before serving.
Storing Leftovers and Reheating
Store leftovers in an airtight container in the refrigerator for up to 3–4 days. The casserole will thicken as it chills, but the flavor stays just as good.
To reheat, warm individual portions in the microwave until heated through, adding a splash of milk or chicken broth if needed to loosen the sauce. For larger portions, you can reheat covered in the oven until hot and creamy again.
Creamy Chicken Spaghetti Casserole
PrintIngredients
- 16 ounces spaghetti
- 1 pound chicken breasts boneless, skinless, cut into bite size pieces
- 1 small yellow onion diced
- 10 ounce can diced tomatoes I don’t drain them (plain diced tomatoes or “mild” Rotel both work great)
- 3 tablespoons butter
- 3 tablespoons flour
- 3 cloves garlic minced
- 2 cups whole milk
- 1 cup chicken broth
- 2 cups shredded cheddar cheese divided
- 1 teaspoon salt
- 1/2 teaspoon black pepper
- 1/2 teaspoon paprika
Instructions
- Preheat oven to 375 degrees F. Spray a 9×13 baking dish with nonstick spray.
- Boil spaghetti until just al dente. Drain and place in the baking dish.
- Season the diced chicken breasts with salt and pepper. In a skillet over medium heat, cook the chicken and onions together until the chicken is cooked through and onions are soft. Place the chicken and onions on top of the spaghetti.
- Pour the can of diced tomatoes on top, I don't drain mine.
- In the same skillet, melt butter. Whisk the flour into the butter and stir for 1 minute until smooth. Add garlic and cook 30 seconds.
- Slowly whisk in milk and chicken broth. Simmer 3–5 minutes until thickened and creamy. Stir in 1½ cups of cheddar cheese until smooth. Add salt, pepper, and paprika.
- Pour the cheese sauce into the baking dish and gently mix until everything is evenly coated. Top with remaining 1/2 cup cheddar cheese.
- Bake for 25–30 minutes, or until bubbly and top noodles are a little crispy. Let rest 5 minutes before serving. Enjoy!
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