Preheat oven to 350F. Prepare a 9x13-inch baking dish by spraying with non-stick cooking spray; set aside.
In a large bowl, combine the cooked pasta, chicken, 1 cup of the cheese, cream of chicken soup, sour cream, salsa, and taco seasoning.
Pour the mixture into the prepared baking dish. Sprinkle the remaining cheese over top of the spaghetti mixture.
Cover with foil and bake at 350F for 25-30 minutes, until the cheese is melted.
Cool slightly before serving.