If not using pre-cooked chicken, boil or bake 2 chicken breasts (seasoned with salt & pepper) until fully cooked (~165°F internal temp). Shred using forks.
In a large bowl, combine mayonnaise, Greek yogurt, Dijon mustard, lemon juice, salt, and black pepper.
Add shredded chicken, celery, red onion, parsley, grapes (if using), and nuts (if using). Mix well.
Taste and add more salt, pepper, or lemon juice if needed.
Refrigerate for at least 30 minutes before serving for best flavor.
Serve on bread, croissants, lettuce wraps, or with crackers.
