1) Rinse chicken breasts and pat dry. Trim off any fat or gristle. In a large bowl, combine taco sauce, lime juice, jalapenos, garlic, salt, and cumin. Add chicken and toss to coat. Cover and marinate, tossing occasionally, 1 to 2 hours at room temperature, or up to 12 hours refrigerated.

2) Prepare a hot fire. Set chicken on an oiled grill 4 to 6 inches from heat. Grill, turning and basting with marinade several times, until chicken is white throughout but still moist, 8 to 10 minutes. Let stand 3 to 5 minutes before cutting or tearing into large strips.

3) While chicken is standing, heat tortillas directly on grill for 20 to 30 seconds per side, or wrap in foil in 2 packages, 6 tortillas to a package, and warm, turning several times, 3 to 5 minutes.

4) To serve, put chicken strips on tortillas. Top with salsa, guacamole, shredded lettuce, and sour cream. Roll up and eat.