Preheat oven to 425 degrees and move rack to top position.
Put the pizza crust on parchment paper. I made my own and cooked it a few minutes before topping. You can buy pizza dough, or pre-made crusts like Boboli for example.
Mix the ranch, garlic, and Parmesan cheese.
Spread the garlic ranch mixture over the crust.
Top with shredded mozzarella
Add cooked chicken
Dice two green onions and half of the tomato.
Add to the pizza
Brush outside of crust with olive oil.
Put on the top rack of the oven and bake at 425 degrees until cheese is melted (about 10 minutes). I broiled mine on low about one and a half minutes as well.