Prep the lettuce: Separate the leaves, rinse, and pat completely dry.
Keep them chilled so they stay crisp.
Make the dressing: In a large bowl, whisk mayonnaise, Greek yogurt, Dijon, lemon juice, and honey. Season with salt and pepper. Taste and adjust the lemon and salt.
Build the salad: Add chicken, celery, red onion, apple, grapes, nuts, and herbs to the bowl.
Fold gently until everything is coated but not smashed.
Chill (optional): For the best flavor, cover and chill 20–30 minutes. The dressing settles and the flavors blend.
Assemble the wraps: Spoon chicken salad into the base of each lettuce leaf. Don’t overfill.
Add avocado or cucumber if using.
Wrap and serve: Fold the sides of the leaf in, then roll from the base up, or simply serve taco-style. Top with extra herbs or a crack of black pepper.
Make it a meal: Serve with sliced tomatoes, a cup of soup, or a side of fresh fruit for balance.