Preheat oven to 425°F. Line jellyroll pan with foil. Sprinkle chicken with Italian seasoning. Place on foil in pan. Bake until brown and crisp, about 10 min. Cool, cut into 1/2"-thick strips.
Place crust on baking sheet, spread with 3/4 cup pizza sauce, leave a 1" border. Top with provolone. Reserve 1/2 cup mozzarella. Layer chicken, onion, remaining mozzarella and remaining pizza sauce over provolone.
Bake until crust is browned and toppings are heated through, about 12 min. Sprinkle with reserved mozzarella. Bake until melted and lightly browned. Top with tomato and basil.