1. Heat oven to 450º.
2. On cookie sheet, place pizza crust.
3. In medium bowl, mix mayonnaise, parmesan, artichokes, and garlic, if using.
4. Spread artichoke mixture over crust, leaving a 1 inch border.
5. Top with 1 cup of the cheese, the chicken and onions.
6. Top with remaining 1/2 cup cheese.
7. Bake 8 to 10 minutes or until cheese is melted and pizza is thoroughly heated.