Preheat your grill to medium-high heat.
In a bowl, mix olive oil, garlic powder, onion powder, smoked paprika, salt, and pepper.
Rub the spice mixture all over the chicken thighs.
Place chicken skin-side down on the grill.
Grill for about 15 minutes, or until the skin is crispy and golden.
Flip the chicken and brush generously with barbecue sauce.
Continue grilling for another 15-20 minutes, basting with more sauce.
Ensure the internal temperature reaches 165°F (75°C).
Remove from the grill and let rest for 5 minutes.
Garnish with fresh parsley before serving.