Preheat your oven to 400°F (200°C) and lightly grease a 9x13-inch baking dish with olive oil.

In the greased baking dish, combine bite-sized pieces of chicken, halved cherry tomatoes, sliced zucchini, and chopped red onion.

Drizzle olive oil over the ingredients, season with oregano, salt, and black pepper, and toss to combine.

Spoon tzatziki sauce over the mixture and gently fold to coat everything evenly.

Bake uncovered for 30-35 minutes until the chicken is cooked through and the vegetables are tender.

Remove from the oven and sprinkle crumbled feta cheese on top before serving.