In a bowl, combine olive oil, lime juice, chili powder, cumin, garlic powder, salt, and black pepper. Add the chicken strips and mix well. Let marinate for at least 15 minutes.

Heat a skillet over medium-high heat. Add the marinated chicken and cook for about 5-7 minutes, or until cooked through.

In the same skillet, add the sliced bell pepper and onion. Sauté for 3-4 minutes until they are tender.

Serve the chicken and vegetables on warmed tortillas. Add sour cream, guacamole, and cheese as desired.