In a small bowl whisk the glaze ingredients until the brown sugar dissolves. Reserve 3 tablespoons of the glaze in a large bowl.
Lightly coat the pork chops on both sides with oil, season evenly with salt and pepper, and brush with the whiskey glaze in the small bowl. Allow the chops to stand at room temperature for 15 to 30 minutes before grilling.
Prepare the grill for cooking over medium heat (400°F).
Lightly coat the apple slices on both sides with oil.
Grill the apples over medium heat, with the lid closed, until crisp-tender and lightly charred, 4 to 6 minutes, turning once or twice. Transfer the apple slices to the large bowl with the reserved whiskey glaze, add the tarragon, and toss to coat.
Grill the chops over medium heat, with the lid closed, until the pork chop registers 145°F (or your preferred doneness), 8 to 10 minutes, turning once or twice. Remove from the grill and let rest for 3 to 5 minutes. Serve the chops warm with the grilled apples.