Make the sauce: Melt butter in a saucepan over medium heat. Add garlic and cook for 30 seconds. Add cream cheese and mix until smooth. Gradually add the milk, stirring until smooth. Stir in parmesan cheese, salt and pepper. Set aside. Prepare Pizza crust: Roll/stretch the pizza dough into a large circle. I like to pre-bake my crust for 4-5 minutes at 425 degrees F (on a pizza stone or baking sheet). Don't pre-bake if it's a thin crust pizza. Assemble: Spoon alfredo sauce over the crust. Add a thin layer of mozzarella, then chopped chicken, more mozzarella, and then a sprinkle of extra parmesan cheese. Bake at 425 degrees F for 8-12 minutes, until cheese is melted and bubbly.