In a small bowl, whisk together the soy sauce and miso until smooth. Whisk in the orange juice and set aside. Season the chicken on both sides with salt and pepper. In a large Dutch oven over medium-high, heat the oil until shimmering. Add the chicken skin down and cook undisturbed until well browned, about 5 minutes. Flip and cook until the second sides are well browned, another 5 minutes. Transfer to a large plate, then pour off and discard all but 2 tablespoons fat from the pot.