Preheat Traeger grill / smoker to 275º F. Make sure there are plenty of wood pellets in the hopper.
Dry chicken thighs with paper towels until they are sticky but not wet. Dispose of marinade.
Sprinkle each thigh generously with dry rub. Rub it under the skin, on top and bottom of each thigh.
1 Tablespoon smoked paprika, 1 Tablespoon onion powder, 1 Tablespoon garlic powder, 1 Tablespoon chili powder, 2 Tablespoons instant coffee granules, 1 teaspoon coarse salt, ½ teaspoon black pepper, ½ cup brown sugar, 6 bone-in chicken thighs
Place thighs on the bottom grill grates with skin side up. Insert thermometer into the thickest chicken thigh.
Smoke at 275º F on Traeger grill until thighs reach an internal temperature of 172º F. This may take anywhere from 1 hour to 1 ½ hours depending on the size of the thighs.
Remove thighs from grill and let rest for 30 minutes before serving. Don't skip this step because it allows the juices to settle back into the meat. Do not cover thighs while resting or the skin will become rubbery.
Notes
To create crispy skin, be sure to dry the thighs completely with paper towels after marinating. Sprinkle generously with dry rub and work into and under the skin.
After smoking, make sure not to cover the chicken thighs or the skins will become rubbery. Allow them to rest uncovered for 30 minutes before serving for best results.
Store leftovers in the refrigerator for up to 3 days in an airtight container. To reheat, do so in a 350 degree oven until heated throughout. Broil skins for a few minutes to crisp them up.
You can skip the marinating if you're pressed for time. Just use the dry rub on the raw chicken.