Place oven rack in lowest position. Heat oven to 425 degrees F. Coat 12-inch pizza pan with cooking spray.
Cook sausage in nonstick skillet over medium heat 10 minutes. Remove; let cool. Slice in thin rounds.
Place crust on prepared pan. Spread with tomato sauce. Sprinkle with Italian seasoning and Parmesan.
Arrange sausage, onion and sweet peppers over sauce. Sprinkle Jack cheese over pizza, leaving a 1- to 2-inch border around edge.
Bake on lowest rack in 425 degree F oven 10 minutes to heat through. Garnish. Makes 6 servings.