Fry tortillas using instructions in notes below. (Unless you have another way you like to prepare corn tortillas for enchiladas.)
Heat 1 tablespoon oil in a large saucepan over medium heat. Add the onion and cook until soft and translucent, about 4 minutes. Increase heat to medium high; add ground beef and cook, stirring occasionally, until browned, about 5 minutes. Stir in the chili powder and season with salt and pepper. Spoon out any accumulated fat. Stir in the beans.
Spoon enough enchilada sauce into the bottom of a 9x13 inch pan to create a thin layer.
Lay a tortilla out on your work surface. Place a couple big spoonfuls of the beef mixture and a sprinkle of both cheeses down the middle of the tortilla. Roll up and place the enchiladas seam-side-down next to each other in the pan. Cover the enchiladas with the remaining enchilada sauce. Sprinkle remaining cheese on top.
Bake 15 to 20 minutes until the sauce is bubbling and the cheese is melted.
Notes
To fry tortillas: In a small skillet, heat ½ inch or less of oil over medium high. When you can flick a drop of water in the oil and get a sizzle, you're ready to fry your tortillas. Place one tortilla in the hot oil and use tongs to press it down so it cooks on both sides. You only need to cook it for about 20 to 30 seconds to soften it up. Remove the tortilla to a paper-towel-lined plate. Repeat with remaining tortillas, placing paper towels in between each cooked tortilla to absorb the oil.