In small saucepan over medium heat, combine 2 cups water, 2 tablespoons Sweet Mustard Rub & Seasoning, salt and brown sugar. Stir until dry ingredients are dissolved. Remove from heat and pour into a large glass or plastic bowl or container. Add 6 cups cold water; stir until cooled. Add pork chops. Cover and refrigerate 6-12 hours.
Remove pork chops from brine and pat dry with a paper towel. Season both sides of pork chops with remaining tablespoon of Sweet Mustard Rub & Seasoning.
Prepare grill to medium heat. Grill pork chops about 22-25 minutes, turning once, until internal temperature reaches 150°F on an instant-read food thermometer. Remove from grill and let rest 3 minutes before serving.