Preheat the oven to 350 degrees F (175 degrees C).
Place melted butter in a shallow dish. Mix crushed cornflakes, Parmesan cheese, parsley flakes, seasoned salt, salt, and pepper together in another shallow bowl.
Dip chicken thighs in butter and then in cornflake mixture. Place in a baking dish.
Bake, uncovered, in the preheated oven until chicken is no longer pink in the center and the juices run clear, about 1 hour. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).