In a medium bowl, combine olive oil, oregano, garlic powder, salt, and pepper to create a flavorful marinade. Add the chicken thighs, ensuring they are fully coated, and let them marinate in the refrigerator for at least 30 minutes.

Heat a non-stick skillet over medium-high heat. Once hot, add the marinated chicken thighs and cook for 5-7 minutes on each side until golden brown and cooked through.

While the chicken is cooking, combine Greek yogurt, crumbled feta cheese, lemon juice, minced garlic, salt, and pepper in a mixing bowl. Stir until smooth, adjusting seasoning to taste.

Once the chicken is cooked, remove it from the skillet and let it rest for a few minutes. Then slice the chicken into strips.

Take warm pita bread and spread a layer of creamy feta tzatziki. Place sliced chicken on top along with cherry tomatoes, cucumber, and red onion. Roll the pita tightly and serve.