One of Nanxun's local specialities is shuāng jiāo miàn (双浇面), a kind of long thin wheat noodle in a rich, dark soy broth. This is the most popular shop in which to try it, though it looks nearly identical to others just like it (to spot it, look for the coal furnace outside).
Once inside, you'll be led into the tiny kitchen to choose your toppings.