Cook the chicken breasts by boiling, baking, or poaching until fully cooked. Let cool slightly, then shred with two forks.
Prepare the Dressing:
In a large bowl, combine Greek yogurt, Dijon mustard, and lemon juice. Mix well.
Add Mix-Ins:
Stir in shredded chicken, celery, red onion, and halved grapes. Add nuts if desired for extra crunch.
Season:
Add salt, pepper, and a pinch of garlic powder. Mix until all ingredients are evenly coated.
Serve:
Serve on a bed of lettuce, in a whole-wheat wrap, or on whole-grain toast.
