In a mixing bowl, whisk together the olive oil, oregano, garlic powder, onion powder, salt, and pepper.
Add the chicken breasts to the bowl, ensuring they are fully coated with the marinade. Cover and refrigerate for at least 30 minutes or up to 2 hours for best flavor.
Preheat a skillet over medium-high heat. Remove the chicken from the marinade and cook it for approximately 6-7 minutes per side, or until cooked through and the internal temperature reaches 165°F (75°C).
Let the chicken rest for 5 minutes before slicing it into thin strips.
While the chicken rests, prepare the tzatziki sauce by mixing the Greek yogurt, lemon juice, diced cucumber, salt, and pepper in a small bowl. Stir well to combine.
Warm the pita breads in a dry skillet for about 1-2 minutes on each side.
Assemble the gyros by placing a generous amount of sliced chicken in the center of each pita. Top with diced tomatoes, red onion, and a dollop of tzatziki sauce.
Garnish with fresh parsley and wrap the pita around the filling.
Serve immediately and enjoy your homemade chicken gyros!
Notes
Marinating the chicken for longer enhances the flavor.