1. Make the honey mustard dressing: In a separate bowl, whisk together the Greek yogurt, Dijon mustard, honey, lemon juice, apple cider vinegar, salt, poppyseeds, and garlic powder until smooth and well blended.
2. Prepare the chicken salad base: In a large bowl, combine the shredded chicken, sliced celery, halved grapes, chopped broccoli, and diced red onion. Add the honey mustard dressing and mix gently to ensure even distribution.
3. Prepare the collard greens (if using): Trim off the thick stem, then use a small knife to carefully shave it down so it's flat. This helps prevent the leaf from breaking and makes rolling easier.
4. Assemble the wraps: Spoon a generous portion of the salad mixture onto a tortilla or collard wrap. Roll up the wrap, slice in half if desired, and serve — or pack for a protein-packed meal on the go.