Preheat the oven to 400°F (204°C).
In a small bowl, whisk together 1/3 cup olive oil, 2 tablespoons dark brown sugar, 1 tablespoon sweet paprika, 1½ teaspoons chipotle chili pepper, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1 teaspoon salt, and ½ teaspoon ground black pepper until smooth.
Trim any excess fat from the chicken thighs and pat them dry with paper towels.
Place the chicken thighs in a large bowl and pour the spice and oil mixture over them. Toss thoroughly so each piece is evenly coated.
Arrange the coated thighs in a single layer in a 9×9-inch baking dish.
Roast in the preheated oven for about 40 minutes, or until the internal temperature reaches 165°F (74°C) and the juices run clear.
Let the chicken rest for 5 minutes, then garnish with fresh chopped parsley and serve.