Slice the chicken breast into thin strips and season evenly with the chili powder, cumin, sea salt, and black pepper.
Heat the olive oil in a large skillet over medium-high heat and add the seasoned chicken strips.
Sauté the chicken for 5-6 minutes until golden brown and fully cooked, then remove from the pan and set aside.
In the same skillet, add the sliced red bell peppers and red onion, cooking for 3 minutes until they are tender-crisp.
Return the chicken to the skillet and pour the fresh lime juice over the mixture, stirring quickly to combine and deglaze the pan.
Warm the whole wheat tortilla in a dry pan for 15 seconds per side until it is soft and pliable.
Spread the mashed avocado onto the center of the tortilla and top with the romaine lettuce and the warm chili-lime chicken mixture.
Fold the sides of the tortilla inward and roll it up tightly to secure the filling before serving.