Preheat oven to 350ºF (177ºC). Boil spaghetti in a large pot until al dente, according to package directions (break the noodles in half if desired). Drain and set aside.
In the large pot, heat the Rotel, cream of mushroom soups, half of the shredded cheddar (1 cup), Velveeta, onion powder, garlic powder, and salt on medium to medium-high heat until the cheese melts, stirring constantly. Turn off the heat.
Stir in the shredded cooked chicken breast and cooked spaghetti noodles a little bit at a time.
Pour the mixture into a lightly greased 9x13 baking dish. Top with the remaining cheddar cheese. Bake for 25 to 30 minutes or until heated through.
Video
Notes
If your shredded chicken is cooked from scratch, be sure to season it with salt and pepper.When stirring in the shredded chicken and cooked spaghetti, mix them in small amounts to make it easier to coat the chicken and noodles.Store in the fridge for 3-4 days.To make ahead, stop after you sprinkle the shredded cheddar on top. Cover tightly and store in the fridge for up to 3-4 days. Follow the baking step when ready to serve.To freeze, stop after you sprinkle the shredded cheddar on top. Wrap tightly and freeze for up to 4 months. Defrost for 24 hours before baking.