Combine lime juice, olive oil, chili powder, cumin, garlic powder, onion powder, sea salt, and black pepper in a large bowl.
Add chicken breasts to the marinade, ensuring they are fully coated. Cover and marinate in the refrigerator for 30 minutes to 2 hours.
Heat a grill or skillet to medium-high heat. Remove chicken from marinade, letting excess drip off, and discard the marinade.
Cook chicken for 6-7 minutes on each side until it reaches an internal temperature of 165°F. Let it rest for 5 minutes before slicing into thin strips.
Warm tortillas on the grill or in a dry skillet for about 30 seconds on each side until soft.
Assemble tacos by placing chicken strips on each tortilla and topping with lettuce, tomatoes, feta cheese, avocado, and cilantro.
Serve immediately and enjoy!