Preheat oven to 425 degrees F. Pour egg into a shallow dish. In another shallow dish combine panko, salt and black pepper. Dip chicken in egg, then in panko mixture, turning to coat. Place chicken in a 15x10-inch baking pan; lightly coat with cooking spray. Place broccolini next to chicken; drizzle with oil. Bake 15 minutes or until chicken is done (165 degrees F).