In a large mixing bowl, combine the shredded chicken, halved grapes, diced celery, red onion, and sliced almonds.
In a separate bowl, whisk together the mayonnaise, Greek yogurt, Dijon mustard, lemon juice, garlic powder, dried parsley, salt, and black pepper until smooth.
Pour the dressing over the chicken mixture.
Gently toss everything together until evenly coated.
Cover and refrigerate for at least 30 minutes to allow the flavors to blend.
Serve chilled in sandwiches, wraps, croissants, lettuce cups, or with crackers.