Preheat oven to 400 degrees F. Lightly coat a 9-inch springform pan with nonstick spray.

Heat olive oil in a large skillet over medium high heat. Working one at a time, add tortilla and cook until crisp and lightly browned, about 1-2 minutes per side, flipping only once.

Place 1 tortilla on the bottom of the springform pan. Spread 2-3 tablespoons sour cream evenly over the top, followed by chicken, sharp cheddar, Pepper Jack and mozzarella. Repeat with 3 more layers; top with remaining tortilla, sour cream and cheeses.

Place into oven and bake for 25-30 minutes, or until the cheeses have melted and the stack is heated through.

Cut into wedges and serve immediately, garnished with avocado and tomato, if desired.