Preheat your oven to 400°F. Cut chicken into bite-sized pieces and marinate if desired.
Slice zucchinis into rounds and set aside.
In a large mixing bowl, combine chicken, zucchinis, tomatoes, onion, and olives. Drizzle with olive oil and season with oregano, garlic powder, salt, and pepper. Toss to coat.
Transfer mixture to a greased 9x13 inch baking dish and spread evenly. Sprinkle feta cheese on top.
Bake for 25-30 minutes until chicken is cooked through and vegetables are tender. Optionally broil for 2-3 minutes for a golden top.
Let cool for a few minutes before serving. Garnish with fresh parsley.