Preheat oven to 400F degrees.
Spray a medium pot with oil and and add garlic, sauté 30 seconds. Add chipotle chiles, chili powder, cumin, broth, tomato sauce, salt and pepper. Bring to a boil. Reduce the heat to low and simmer for 5-10 minutes, to let the flavors meld. Set aside until ready to use.
Heat the oil in a medium skillet over medium-high heat. Sauté onions and garlic on low until soft, about 2 minutes. Add beans, salt, cilantro, cumin, oregano, chili powder, tomato sauce, broth, and cook 4 to 5 minutes. Remove from heat.
Spray a 13 by 9-inch glass or ceramic baking dish with oil. Put 1/3 cup bean mixture into each tortilla and roll it.
Place on baking dish seam side down, top with sauce. Then top with cheese.
Cover with foil and bake in the oven on the middle rack for 20-25 minutes, until it's heated through and the cheese is melted. Garnish with scallions or cilantro.