Make the taco marinade by stirring together lime juice, olive oil, garlic, cumin, chili powder, cilantro, salt, and pepper.
Place chicken in a large resealable bag. Pour marinade over chicken and seal bag. Marinate in fridge for 1–6 hours.
Cook chicken thoroughly on a preheated grill, about 5 minutes per side. Let rest briefly, then dice chicken into bite-sized cubes. Layer onto warm R3-friendly tortillas or tortilla alternatives with desired toppings.