Using a medium mixing bowl, add in the chicken, garlic, olive oil, and spices then mix/toss to combine. Cover the bowl then place in the fridge to marinate for about thirty minutes or up to overnight. Next, take the bowl out of the fridge, remove the chicken and discard the marinade.
Preheat a grill to medium-high, grease the grates then add in the chicken. Grill the chicken for about nine to ten minutes on both sides until the chicken is cooked through and no longer pink, set aside.
To make the sauce, using a food processor or a high-speed blender, add in the cilantro, Greek yogurt, oil, jalapeño, garlic, lime juice, and salt to taste then blend until the mixture becomes creamy. To assemble, place the lettuce on a flat plate, add in the rest of the toppings alongside with the prepared sauce then serve.