Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente according to package instructions. Drain and set aside.
In a large skillet, melt the butter over medium heat. Add the chopped onion and minced garlic, sauté until translucent and fragrant, about 3-4 minutes, until onions are soft and slightly golden.
1 pound spaghetti
Add the cooked chicken to the skillet and cook for another 2-3 minutes until heated through. Season with salt and pepper to taste.
1 pound spaghetti
Pour in the Rotel diced tomatoes with green chilies and stir to combine. Let the mixture simmer for 3-5 minutes until it slightly thickens and flavors meld.
1 pound spaghetti
Stir in the sour cream and shredded cheddar cheese, cooking until the cheese melts and the sauce becomes creamy and smooth, about 2-3 minutes. Adjust seasoning as needed.
1 pound spaghetti
Add the cooked spaghetti to the skillet and toss to coat evenly with the sauce. Cook for another 2 minutes until heated through.
1 pound spaghetti
Transfer the pasta to serving plates, top with additional shredded cheese if desired, and serve hot.
1 pound spaghetti
