Preheat your grill pan or outdoor grill over medium-high heat.
In a medium bowl, combine olive oil, oregano, garlic powder, paprika, salt, and pepper. Add the chicken breasts and coat thoroughly with the spice mixture. Let it marinate for about 15 minutes.
Grill the marinated chicken for about 6-7 minutes per side, or until fully cooked and golden brown. Remove from heat and let it rest for a few minutes before slicing it into strips.
While the chicken is resting, prepare the pita pockets: Warm the pita breads on the grill for about 1-2 minutes on each side until slightly crispy.
Spread a generous amount of tzatziki sauce inside each pita pocket.
Fill each pita with mixed greens, sliced grilled chicken, cherry tomatoes, diced cucumber, and red onion.
If desired, sprinkle crumbled feta cheese on top for added flavor.
Garnish with chopped fresh parsley before serving.
Serve immediately while warm and enjoy!
Notes
Feel free to customize the vegetables and toppings to your liking.