In a large mixing bowl, combine the cooked chicken, chopped dill pickles, mayonnaise, Greek yogurt, and Dijon mustard.
Add the fresh dill, garlic powder, onion powder, salt, and pepper. Mix well until all ingredients are evenly coated.
If using, fold in the finely chopped celery and red onion for added crunch and flavor.
Taste and adjust seasoning if necessary. If you prefer a creamier texture, add more mayonnaise or yogurt.
Cover the bowl and refrigerate for at least 30 minutes to allow the flavors to meld.
Serve chilled on a bed of lettuce, in a sandwich, or with crackers.