In a bowl, mix together the olive oil, dried oregano, garlic powder, salt, and pepper. Add the boneless, skinless chicken thighs to the bowl and coat them well with the marinade. Cover the bowl and let it sit for at least 30 minutes.

Heat a skillet over medium-high heat. Once hot, place the marinated chicken thighs in the skillet. Cook each side for about 5 to 7 minutes until the chicken is golden brown and reaches an internal temperature of 165°F (75°C).

In a bowl, combine the plain Greek yogurt, crumbled feta cheese, lemon juice, minced garlic, and a pinch of salt and pepper. Mix everything together until it is smooth and creamy.

Once the chicken is cooked, take it off the heat and let it rest for a minute. Then, slice the chicken into strips.

Take a pita bread and spread a generous amount of tzatziki sauce on it. Add a few strips of the cooked chicken, then top with halved cherry tomatoes, diced cucumber, and thinly sliced red onion. Roll up your pita and enjoy!