Preheat the oven to 375 degrees F (190 degrees C).
Mix miso paste, butter, honey, and rice vinegar together in a bowl. Rub mixture on chicken thighs, making sure to rub under and over the skin. Place thighs in a large roasting pan with enough distance between them to roast evenly.
Bake in the preheated oven until chicken is no longer pink in the center and juices run clear, about 30 minutes.
