Preheat the oven to 425°F (220°C).
Pat the chicken breasts dry with paper towels. If needed, pound them to an even thickness.
In a small bowl, mix together the paprika, garlic powder, onion powder, smoked paprika, salt, black pepper, and chili powder.
Rub the chicken breasts with olive oil, then coat both sides evenly with the seasoning mixture.
Place the chicken in a lightly greased baking dish or on a parchment-lined baking sheet.
Bake for 15 minutes.
Remove the chicken from the oven and brush both sides generously with the barbecue sauce.
Return to the oven and bake for another 5 to 8 minutes, or until the internal temperature reaches 165°F (74°C).
For a caramelized finish, switch the oven to broil and cook for 1 to 2 minutes, watching carefully to prevent the sauce from burning.
Brush with melted butter, if using, and let the chicken rest for 5 minutes before serving.
Garnish with chopped parsley and serve warm.