Place chicken drumsticks in a large resealable freezer bag. Add buttermilk, 1/4 cup oil, maple syrup, peppercorns, salt, taco seasoning, garlic, paprika, cayenne pepper, and liquid smoke. Seal the freezer bag and squish everything in the bag until the drumsticks are coated. Marinate the drumsticks in the refrigerator, 8 hours to overnight.
Preheat the oven to 425 degrees F (220 degrees C). Line a roasting pan with aluminum foil.
Remove drumsticks from the marinade and shake off excess. Place drumsticks in the prepared pan and drizzle with 2 tablespoons oil. Discard the remaining marinade.
Roast in the preheated oven until the drumsticks are well browned, about 30 minutes.