01 - Whisk together lime juice, lime zest, olive oil, garlic, chili powder, cumin, smoked paprika, salt, and black pepper in a large bowl. Add chicken breasts and turn to coat evenly. Cover and refrigerate for at least 20 minutes, up to 2 hours.
02 - Preheat a grill or skillet to medium-high heat. Remove chicken from the marinade and cook for 6 to 7 minutes per side until the internal temperature reaches 165°F.
03 - Combine diced avocados, tomato, red onion, cilantro, lime juice, and salt in a bowl. Gently toss until evenly mixed.
04 - Transfer cooked chicken to plates. Sprinkle shredded cheese over each breast while hot so it melts slightly, if desired.
05 - Top each chicken breast with a generous spoonful of avocado mixture. Garnish with lime wedges and extra cilantro. Serve immediately.