In a bowl, combine olive oil, chili powder, cumin, garlic powder, smoked paprika, lime juice, salt, and pepper. Add the chicken breasts and coat them well with the marinade. Cover and let marinate for at least 30 minutes (or up to 2 hours in the fridge for more flavor).
Preheat a grill or skillet over medium-high heat. Remove the chicken from the marinade and cook for about 6-7 minutes on each side, or until fully cooked and juices run clear. The internal temperature should be 165°F (75°C). Once done, let the chicken rest for 5 minutes before slicing.
While the chicken is resting, warm the corn tortillas in a dry skillet over medium heat until soft and pliable (about 30 seconds on each side).
Thinly slice the rested chicken and divide it evenly among the tortillas. Top each taco with fresh avocado slices and a generous amount of shredded red cabbage.
Sprinkle chopped cilantro on top of each taco, and serve with lime wedges on the side for guests to squeeze over their tacos.
Notes
For extra flavor, marinate the chicken for up to 2 hours.