In a large mixing bowl, combine plain Greek yogurt, shredded cucumber, fresh lemon juice, chopped fresh dill, garlic powder, and a pinch of kosher salt and black pepper. Stir well until blended into a creamy tzatziki sauce.

Gently fold in shredded cooked chicken, finely chopped red onion, chopped kalamata olives, and crumbled feta cheese using a rubber spatula.

Incorporate chopped flat-leaf parsley and adjust seasoning, adding more salt, pepper, or lemon juice if needed.

Transfer the salad into serving bowls or a large platter and serve it in pitas, over greens, or as a dip. Store in an airtight container in the refrigerator for up to 4 days.