In a bowl, stir masa flour, baking powder, salt, and broth until dough holds together well, adding a little water if needed.
Divide dough into 4 equal portions. Shape each portion into a 6-inch-long log on a sheet of waxed paper. Pat each log into a 1/8-inch-thick oval, about 4 by 8 inches. (If shaped ahead, stack with waxed paper, wrap airtight, and refrigerate up to 2 hours.)
Place a griddle or 2 frying pans (10 to 12 in.) over medium-high heat. When pan is hot, flip masa dough onto pan and peel off paper. Cook until bottom of masa is light brown, about 3 minutes. Use a wide spatula to turn huaraches over.
Spread about 1/4 of the beans over each huarache. Cover beans with 1/4 of the chicken topping. Cook until huarache bottoms are lightly browned, 2 to 3 minutes. With a wide spatula, transfer to plates.
Top huaraches equally with shredded cabbage, salsa, cheese, sour cream, salt, and pepper to taste.
Nutritional analysis per huarache without topping.