Begin by preheating your grill or grill pan over medium-high heat until hot.
In a mixing bowl, combine the extra virgin olive oil, dried oregano, garlic powder, sea salt, and freshly ground black pepper. Mix well and then rub this flavorful marinade all over the chicken breasts, ensuring they are evenly coated.
Place the seasoned chicken onto the grill and cook for approximately 6-7 minutes on each side, or until the chicken is no longer pink in the center and the juices run clear. Once cooked, transfer the chicken to a cutting board and let it rest for 5 minutes.
While the chicken rests, craft a simple tzatziki sauce by whisking together the plain Greek yogurt, fresh lemon juice, and a pinch of salt in a small bowl until smooth and creamy.
After resting, slice the grilled chicken breasts into thin strips, creating tender pieces perfect for stuffing.
To warm up the pita breads, place them in a dry skillet over low heat or pop them in the microwave for about 10 seconds, just until they become soft and pliable.
Assembly time! Gently open each pita pocket and layer in the sliced grilled chicken, followed by a handful of halved cherry tomatoes, diced cucumber, thinly sliced red onion, and a generous sprinkle of crumbled feta cheese.
Add a drizzle of the homemade tzatziki sauce over the stuffed fillings in each pita, then top with a bright garnish of finely chopped fresh parsley.
Serve your delicious Greek chicken stuffed pitas immediately while warm, accompanied by extra lemon wedges on the side for those who enjoy a fresh squeeze of citrus.