Pat the chicken thighs completely dry with paper towels, inside and out. This step is crucial for achieving crispy skin. Drizzle olive oil over each thigh and rub thoroughly all over. If you gently lift the skin at one edge, you can work some oil underneath as well.

Mix all spices (garlic powder, onion powder, paprika, thyme, rosemary, salt, pepper, smoked paprika) in a small bowl. Sprinkle evenly over both sides of the thighs, pressing gently to help spices adhere.

Place seasoned thighs skin-side up on a parchment-lined rimmed baking sheet (18x13-inch half-sheet pan works well). Space them at least an inch apart to prevent steaming.

Preheat oven to 425°F. Place baking sheet on middle rack and roast for 35 to 40 minutes until internal temperature reaches 165°F when measured in the thickest part. The skin should be deep golden brown and juices should run clear. If not at 165°F after 40 minutes, continue cooking and check every 5 minutes.

Let chicken rest for 5 minutes after removing from oven. This allows juices to redistribute throughout the meat. Serve immediately while skin is still crispy.