1Heat pizza crusts as directed on package if desired.
2Meanwhile, heat oil in 10-inch skillet over medium-high heat. Cook celery in oil 4 to 5 minutes, stirring occasionally, until crisp-tender; reduce heat. Stir in chicken and pesto. Cook, stirring occasionally, until hot.
3Spoon chicken mixture onto pizza crusts. Mix cheese and lettuce; sprinkle over chicken mixture. Cut each pizza crust in half.