In a medium bowl, combine ¼ cup of olive oil, 3 minced garlic cloves, 1 tablespoon of dried oregano, 1 teaspoon of ground cumin, and salt and pepper to taste. Add the boneless, skinless chicken breasts, ensuring they are fully coated in the marinade. Cover and let marinate for at least 30 minutes in the refrigerator.

Preheat your grill or skillet over medium-high heat. Place the marinated chicken breasts on the grill and cook for about 6–7 minutes on each side until the internal temperature reaches 165°F. Remove from heat and let rest for 5 minutes before slicing thinly.

In a small mixing bowl, whisk together 1 cup of plain Greek yogurt and the juice of one whole lemon until smooth. Adjust seasoning with a pinch of salt.

In a separate bowl, combine 1 cup of diced tomatoes, 1 cup of diced cucumber, ½ cup of finely chopped red onion, ½ cup of sliced Kalamata olives, and ½ cup of crumbled feta cheese. Toss gently to mix.

To prepare your corn tortillas, heat a dry skillet over medium heat. Briefly warm each tortilla for about 30 seconds on each side.

On each warmed tortilla, layer in slices of grilled chicken, followed by a scoop of the salad mixture. Drizzle the yogurt sauce over the top.

Finish tacos with a sprinkle of fresh parsley and serve immediately.