Preheat the oven to 350°F (177°C).

Add the ground chuck to a 12-inch skillet. Brown the meat, stirring occasionally, for 6 to 7 minutes. Once the meat is no longer pink, spoon off and discard the grease.

Add the onions, garlic, and jalapeño to the beef and continue cooking until the onions are translucent, about 6 minutes. Sprinkle the taco seasoning and kosher salt over the mixture, add the beef stock (or water), and stir until evenly coated. Then, add the drained black beans and stir to combine.

Pour 2 ½ cups of enchilada sauce into a pie dish. Dip corn tortillas in the sauce and line the bottom of the casserole dish with them. Sprinkle ¾ cup of cheese, half of the meat mixture, and another ¾ cup of cheese. Repeat layering with more tortillas, 1 cup of cheese, remaining beef mixture, and 1 cup of cheese. Top with remaining tortillas and enchilada sauce.

Cover with aluminum foil and bake for 25 minutes. Remove the foil and bake until the cheese is melted and bubbling, another 10 to 12 minutes.

Allow to cool for 10 to 15 minutes. Cut into squares and serve garnished with sour cream, chopped cilantro, and jalapeño slices.