In a medium mixing bowl, whisk together the mayonnaise, lemon juice, chopped parsley, kosher salt, and ground pepper until smooth and creamy.
In a separate large bowl, combine the diced cooked chicken, halved or quartered grapes, chopped apple, chopped celery ribs, and chopped or sliced nuts.
Pour the dressing over the chicken mixture and gently stir until everything is evenly coated.
Cover the salad and chill in the refrigerator for at least 1 hour to let the flavors meld.
Serve the chicken salad on bread, croissants, pita, crackers, or in lettuce cups.