In a prep bowl, combine 2 Tbsp brown sugar, 1 1/2 tsp salt, 1/4 tsp black pepper, 1 tsp onion powder, 1 tsp garlic powder, 2 tsp cumin, 2 tsp chili powder, and 1 Tbsp paprika.
Now place 6-9 chicken thighs (bone-in, skin-on) into a gallon-sized ziplock bag.
Then add the spice mixture inside, along with 3 Tbsp olive oil.
Close up the bag and massage the spices and oil into the chicken. Let the chicken marinate for at least two hours or preferably overnight in the refrigerator.
Then fill your pellet smoker with hickory or applewood smoked pellets and turn it on to 225 degrees Fahrenheit. Then place the chicken skin side up and cook for about 2 hours or until the internal temperature of the chicken is at least 165°F. Make sure to insert the meat thermometer into the thickest part of the chicken (away from the bone).
Then flip the chicken and bring the heat up to 500 degrees Fahrenheit for about 5 minutes to give it a nice char and crisp up the skin a little. Remove from the smoker and serve hot.