In a bowl, combine the sliced chicken, olive oil, lime juice, lime zest, chili powder, cumin, garlic powder, salt, and pepper. Mix well to coat the chicken and let it marinate for at least 15 minutes (up to 1 hour for more flavor).
Heat a large skillet or frying pan over medium-high heat. Once hot, add the marinated chicken to the skillet.
Cook the chicken for about 5-7 minutes, stirring occasionally until it is no longer pink and cooked through.
Add the sliced bell pepper and onion to the skillet. Sauté for another 5 minutes until the vegetables are tender and lightly charred.
Taste and adjust seasoning if necessary. Remove from heat.
Warm the tortillas in a separate pan or microwave until pliable.
To serve, place a generous amount of the chicken and vegetable mixture on each tortilla and top with fresh cilantro and any optional toppings you desire.
Notes
Marinate the chicken for longer for enhanced flavor.