1. Preheat broiler.
2. Place corn on a jelly-roll pan; broil 18 minutes or until charred on all sides, rotating every 6 minutes. Cut kernels from corn; place kernels in a medium bowl. Cut tomatoes into quarters. Add tomatoes to corn, and sprinkle corn mixture with black pepper and salt.
3. Heat tortillas according to package directions. Divide chicken evenly among tortillas; top each taco with 1/4 cup corn mixture and 2 avocado slices. Serve with lime wedges, if desired.