Heat spaghetti sauce over low heat until heated through. Cover to keep warm. Place one chicken breast between 2 sheets of wax paper. Flatten with rolling pin or meat mallet. Repeat with remaining chicken breasts. Combine bread crumbs, parmesan cheese, and margarine in small bowl. Mix well. Add chicken and turn to coat. Spray a nonstick skillet with nonstick spray. Heat to medium heat and add chicken. Cook 4-6 minutes per side or until done. Place chicken on plate and sprinkle with mozzarella cheese. Pour warm spaghetti sauce over.