Slice the chicken breasts into thin strips.
Combine olive oil, lime juice, chili powder, cumin, salt, and pepper in a bowl.
Add the chicken strips to the marinade and let sit for 10-15 minutes.
Heat a skillet over medium-high heat and add the marinated chicken.
Cook the chicken for about 5-7 minutes until browned and cooked through.
Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced bell peppers and onion.
Sauté the vegetables for about 5 minutes until they are tender.
Add the cooked chicken back to the skillet and mix everything together.
Serve the chicken and vegetable mixture in the tortillas with your favorite toppings.