Preheat oven to 350 degrees. Lightly spray a 9x13 inch pan with cooking spray and set aside. Cook the pasta in a large pot according to package directions. In a large bowl combine pasta, cooked chicken, 1 cup cheese, spinach, and artichoke.
To make the alfredo sauce: In a medium saucepan add butter, heavy whipping cream, and cream cheese. Cook over medium heat and whisk until melted. Add the minced garlic, garlic powder, italian seasoning, salt and pepper. Continue to whisk until smooth. Add the grated parmesan cheese. Bring to a simmer and continue to cook for about 3-5 minutes or until it starts to thicken.
Add alfredo sauce to the large bowl and toss with ingredients to coat. Pour into the prepared 9x13 inch pan. Add remaining cheese to the top of the casserole.
Cover with foil and bake for 30 minutes or until cooked throughout and bubbling on the sides.