Start by removing the skin from the rotisserie chicken and chop the meat into bite-sized pieces. Discard any bones.
In a large mixing bowl, combine the mayonnaise, Greek yogurt, lemon juice, Dijon mustard, garlic powder, salt, lemon pepper, and black pepper. Whisk together until smooth and creamy.
Add the chopped chicken, diced celery, finely chopped red onion, and diced scallion to the bowl with the dressing. Gently fold the ingredients together until everything is evenly coated.
Cover the bowl with plastic wrap and let the chicken salad chill in the refrigerator for at least 30 minutes.
After chilling, give the salad a good stir and serve it on a bed of greens, in a sandwich, or in a wrap.
