Begin by bringing a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente, typically about 8-10 minutes. Once done, drain the pasta in a colander and set it aside to cool.

In a spacious pot over low heat, combine the undrained Ro*Tel tomatoes, cream of mushroom soup, Velveeta, and cream cheese. Stir continuously until the mixture is smooth and bubbly, taking about 5-7 minutes.

Once your sauce is bubbling, sprinkle in the garlic powder and onion powder, mixing well. Then, fold in the shredded chicken and the cooked spaghetti, stirring until thoroughly coated.

Preheat your oven to 350°F (175°C) while preparing your casserole dish. Pour the chicken spaghetti mixture into a greased 9x13-inch baking dish and top with shredded cheddar cheese.

Cover the baking dish tightly with aluminum foil and bake for about 30 minutes. Remove the foil during the last 5-10 minutes for a golden top.

Once baking time is complete, remove the casserole from the oven and let it cool for about 5-10 minutes before serving.