How to Make It
Preheat the oven to 450°. Set a rack over a baking sheet. Rub the chicken with 2 tablespoons of the oil and season with salt and pepper. Arrange the chicken on the rack on the baking sheet. Roast for 45 minutes, until golden and cooked through. Let cool slightly, then discard the chicken skin and shred the meat.
Meanwhile, in a large cast-iron skillet, heat the remaining 2 tablespoons of oil. Add the tomatillos, jalapeño, garlic and scallions. Cook over moderately high heat, stirring, until the tomatillos are softened, about 15 minutes. Add the broth and bring to a boil, then simmer over moderate heat, stirring occasionally, until thickened, 10 minutes.
Into a blender, scrape the tomatillo mixture and add the cilantro; puree until smooth. Return the sauce to the skillet and add the shredded chicken. Simmer over moderate heat, stirring, until the chicken is heated through, 2 minutes; season with salt and pepper. Serve the chicken with tortillas, radishes, pico de gallo and sour cream.