1. Place chicken in large resealable plastic bag or glass dish. Add 1/4 cup of the marinade; turn to coat well. Refrigerate 30 minutes or longer for extra flavor.

2. Meanwhile, mix avocado and 2 tablespoons of the remaining marinade in small bowl. Set aside. Remove chicken from marinade. Discard any remaining marinade.

3. Broil or grill over medium-high heat 5 to 7 minutes per side or until cooked through, brushing with remaining 2 tablespoons marinade halfway through cooking time. Cut chicken into thin slices. Spread avocado mixture on tortillas. Divide chicken among tortillas. Top with assorted topping, if desired.