A few notes:

• Scale this recipe up or down as needed. For a 10-inch square or round baking dish, these proportions are about right. Use more or less sauce if you are using a larger or smaller pan. I am using this tart pan here. For a 9×13-inch pan, I imagine using 1.5 times this recipe will be about right. 
• I am partial to using flour tortillas, which is not traditional, but I find them to be more flavorful. When I have a stash of Caramelo tortillas on hand, that is my preference. When I don’t, I look for the tortillas made from a blend of flour and corn (Trader Joe’s, Whole Foods) or I make them from scratch (this one is made with sourdough starter or discard). If you are using Caramelo tortillas, char them on one side in a skillet. If you are using standard flour tortillas, warm them in a skillet before using — this makes them more pliable and therefore easier to roll. 
• The success of this recipe relies on using super flavorful black beans. This is my favorite way to prepare black beans: Simplest Slow Cooker Black Beans. If you are using canned beans, consider draining and rinsing them, then placing them in a pot with enough water to cover, a healthy splash of olive oil, a bay leaf, some crushed red pepper flakes, a good pinch of salt, and a clover of garlic. Simmer gently for 15-20 minutes or until the beans have taken on some flavors from the broth. 
• See notes in the post above for freezing the unbaked enchiladas.