Dice your cooked chicken into bite-sized pieces and place it in a large mixing bowl.

Add the sweet pineapple chunks and chopped celery to the bowl. Gently mix these ingredients together using a spatula.

In a separate medium bowl, combine the mayonnaise, Greek yogurt, and sweet relish. Stir until the mixture is creamy and well-blended.

Pour the creamy dressing over the chicken mixture in the large bowl. Sprinkle in salt and black pepper to taste, then fold the dressing gently into the mixture until everything is well-coated.

If using chopped walnuts, fold them into the salad just before serving.

Serve the Hawaiian Chicken Salad on crisp lettuce leaves, garnished with extra pineapple chunks or nuts.