In a large mixing bowl, combine Greek yogurt, shredded cucumber, and lemon juice. Stir in dill, garlic powder, salt, and pepper until smooth.

Add shredded chicken, red onion, olives, feta cheese, and parsley to the tzatziki base. Mix gently until evenly combined.

Taste the mixture and adjust the seasoning with more lemon juice, salt, or pepper to your liking.

Cover the bowl with plastic wrap or transfer to an airtight container and chill in the refrigerator for at least 30 minutes.

Before serving, remove from the refrigerator, transfer to a serving bowl, and garnish with additional feta, dill, or olive oil.