In a mixing bowl, combine the sliced chicken with 1 tablespoon of olive oil and 2 tablespoons of taco seasoning. Toss thoroughly to coat the chicken evenly.
Heat the remaining tablespoon of oil in a large non-stick skillet over medium heat. Add the seasoned chicken to the skillet and cook, stirring frequently, for approximately 3-4 minutes, until fully cooked. Transfer the chicken to a plate and set it aside.
In the same skillet, add the sliced onion and bell peppers. Sauté, tossing occasionally with tongs, until the vegetables are tender yet slightly crisp. Sprinkle with the remaining tablespoon of taco seasoning.
Return the cooked chicken to the skillet, stirring to combine with the vegetables. Serve immediately with tortillas, topping with a squeeze of fresh lime juice. Add sour cream and guacamole to taste.