Step 1: Marinate the Chicken : In a large mixing bowl, whisk together olive oil, lime juice, garlic, chili powder, cumin, smoked paprika, coriander, salt, pepper, and cayenne. Add the sliced chicken to the marinade and toss to coat well. Cover and refrigerate for at least 30 minutes (or up to 4 hours for deeper flavor).
Step 2: Prepare the Vegetables : Slice the bell peppers and onions into thin strips. Toss them with 1 tablespoon olive oil and season lightly with salt and pepper.
Step 3: Cook the Chicken : Heat a large cast-iron skillet or heavy pan over medium-high heat. Add a drizzle of oil and cook the marinated chicken in batches for 4–5 minutes per side, until golden brown and cooked through. Remove and set aside.
Step 4: Sauté the Vegetables : In the same skillet, add a bit more oil if needed. Add the sliced peppers and onions and sauté for 5–7 minutes until slightly charred and tender-crisp. Add the cooked chicken back into the skillet and toss everything together for 1–2 minutes until well combined and heated through.
Step 5: Warm the Tortillas : Heat tortillas in a dry skillet or wrap them in foil and warm in a 300°F (150°C) oven for a few minutes. Keep covered in a clean towel to stay soft and warm.
Step 6: Assemble the Fajitas Lay a warm tortilla flat. Add a few strips of chicken and some peppers and onions. Top with your favorite extras — sour cream, guacamole, cheese, salsa, or a squeeze of lime juice. Roll or fold, and enjoy!