Preheat a grill to medium. Combine the brown sugar, paprika and mustard powder in a small bowl. Season the pork chops with salt and pepper and rub all over with the spice mixture; set aside.
Whisk the honey mustard, lemon juice, 1/2 teaspoon salt and a few grinds of pepper in a large bowl; whisk in the olive oil. Add the carrots, parsley, chives and sunflower seeds and toss well. Refrigerate the carrot salad while you cook the pork chops.
Lightly oil the grill grates. Grill the pork chops, covered, until marked, about 4 minutes per side. Uncover and cook until a thermometer inserted into the pork registers 145 degrees F, about 1 more minute. Serve with the carrot salad and honey mustard.