Heat oven to 400°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray.
In large microwavable bowl, microwave potatoes uncovered on High 3 to 5 minutes or until completely thawed and hot, stirring once or twice. Stir in dressing, Cheddar cheese and cooking sauce until well mixed. Spoon into baking dish. Place chicken strips on top.
Cover; bake 15 minutes. Uncover; bake 15 to 20 minutes longer or until potatoes are tender and chicken is hot in center of thickest pieces. Sprinkle with blue cheese and celery.