Prepare a 12" round pizza pan with cooking spray; set aside. On a lightly floured surface, roll dough out to a 12" circle. Place in prepared pan, pressing to fit edges. Prick several time with a fork. Bake in a 425 degree oven for 15 minutes, or until light brown. Remove from oven and set aside. In a skillet, cook chicken, onions, and bell peppers. Cook until no pink remains in chicken and vegetables are tender. Add ketchup, mustard, salt, and black pepper. Mix well. Spread meat mixture evenly over crust. Sprinkle with pickles and cheese. Bake for 12 minutes or until crust is crisp and brown. Cut and serve.