Set a large pot of water to boil to cook the noodles. Cook to al dente according to package directions. Salt water to preference.
Cut breasts into strips or small pieces for faster and even cooking. Season with salt and pepper on both sides. Add any extra seasoning you may like such as garlic powder, onion powder, or a seasoned salt.
Heat oil in a large skillet over medium-high heat. Add the chicken and cook for 3 or 4 minutes per side or until cooked through. Remove chicken to a cutting board and shred or cut into bite-sized pieces.
Reduce heat to medium or medium low. Add the butter in the same pan. Once melted, add the onions and cook for 3 to 4 minutes. Add chopped garlic and cook one minute more.
Sprinkle flour over the onion mixture and cook for one or two minutes. Now, slowly add the broth stirring with a whisk to keep the mixture from getting clumpy. When the broth mixture is smooth, stir in the milk until combined. Add cubed Velveeta and stir until melted and combined. Now add one cup of the shredded cheddar cheese and stir until smooth.
Next, add the Rotel. If you want a thick sauce, drain the Rotel. If you like a thinner sauce, add the liquid from the can. I like to add the liquid for extra flavor. Mix it together and add the shredded chicken and cooked spaghetti noodles.
Top with remaining shredded cheese and serve!
Notes
You can serve this dish straight from the pan, but if you prefer you can transfer the spaghetti to a casserole dish that's been greased, top with extra cheese, and bake for 20 to 30 minutes in a 350 degree oven.Add some extra veggies by slicing some button mushrooms, or chopping up a green bell pepper (or red) and adding it to the pan with the onions. Use jalapeño for a kick.A great addition is a cup of corn or black beans for added fiber.