Clean and grease grill grate. Preheat grill to medium heat (350˚F). Season pork with salt and pepper and coat with 1 tablespoon of oil. Place pork chops on grill and cook for 8-10 minutes turning once. Baste with 2 tablespoons of sauce during last 5 minutes of cooking. Internal temperature must reach 145˚F. Allow to rest for 3 minutes; chop into bite size pieces and toss with remaining sauce.
While pork is cooking, toss together tomatoes, avocados, cilantro and remaining oil in a medium bowl; season with salt and pepper. In small bowl, combine sour cream and relish. Heat tortillas according to package directions and serve each topped with pork, salsa, a dollop of sour cream mixture, and lettuce.