Bring potatoes to boil in lightly salted water in large saucepot. Reduce heat and simmer 10 minutes or until fork-tender. Drain well. Cool slightly.
Mix mayonnaise, vinegar, celery seed, garlic powder, salt and pepper in large bowl until well blended. Add potatoes, chicken and celery; toss gently to coat.
Serve immediately or refrigerate until ready to serve. Sprinkle with cheese before serving.