Sauté first 4 ingredients in hot oil in a large skillet over medium-high heat 8 to 10 minutes or until vegetables are tender. Drain well.
Unroll pizza crust; press or pat into a lightly greased 13- x 9-inch pan.
Bake crust at 400° for 12 to 14 minutes. Spread 1/2 cup barbecue sauce evenly over top of pizza crust in pan. Arrange chicken strips evenly over barbecue sauce, top with onion mixture, and sprinkle evenly with cheese.
Bake at 400° for 8 to 10 minutes or until cheese melts. Garnish, if desired. Serve with extra sauce for dipping.