Preheat the oven to 250°F. Season bison with salt and maple sugar. Film a Dutch oven or large flame-proof baking dish with the oil and set over high heat. Sear the bison on all sides until dark and crusty, about 10 minutes. Remove the bison and set aside.
Stir in the stock and sage, scraping up any crusty bits at the bottom of the baking dish. Add the hominy, sumac, and maple syrup and return the meat to the baking dish. Cover the Dutch oven or the baking dish tightly, using aluminum foil if necessary. Place the bison in the oven and cook until so tender it falls from the bone, about 3 hours.
Remove from the oven. Tent the meat with foil to keep warm. Strain the remaining stock into a saucepan and reserve the hominy. Set the stock over high heat, bring to a boil and reduce the liquid by half. Taste and adjust the seasoning. Carve the bison and serve over the hominy with the sauce drizzled on top of the meat.