Rub chicken with chili powder.
In large nonstick skillet, over medium heat, heat oil. Add chicken; cook 4 to 5 minutes on each side, or until browned.
Meanwhile, in medium bowl, combine tomatoes, chiles, lime juice and pepper sauce; add to skillet. Reduce heat to medium-low; cover and simmer 12 to 15 minutes, or until chicken is cooked through.
To serve, place chicken on bed of shredded lettuce; top with sauce from skillet. Sprinkle with shredded cheese and garnish with lime; accompany with a basket of warm tortillas. Serves 4.