01 - In a large bowl, combine the diced chicken, chopped pecans, celery, grapes, and red onion.
02 - In a small bowl, whisk together the mayonnaise, Greek yogurt, Dijon mustard, lemon juice, salt, and black pepper until smooth.
03 - Pour the dressing over the chicken mixture and toss gently until everything is evenly coated.
04 - Fold in the chopped parsley if using.
05 - Cover and refrigerate for at least 30 minutes before serving to allow flavors to meld.
06 - Serve chilled, on a bed of lettuce, in a sandwich, or with crackers.