Preheat the oven to 350°F and lightly grease a 9×13-inch casserole dish.

Heat a large skillet over medium-high heat. Add the ground beef, breaking it apart as it cooks, until browned, about 7–10 minutes. Drain excess grease.

Stir in the taco seasoning and water until well combined.

Add 1½ cans of enchilada sauce along with the diced tomatoes, black beans, corn, and jalapeños. Stir to combine, reduce heat to medium, and bring to a simmer. Let simmer for 5 minutes.

Pour the remaining enchilada sauce into the bottom of the casserole dish, then layer 6 tortillas over the top (they should overlap).

Spread ⅔ of the beef mixture over the tortillas and sprinkle with half of the cheddar and pepper jack cheeses.

Add another layer of 6 tortillas, followed by the remaining filling and remaining cheese.

Bake uncovered for 25–30 minutes, or until the cheese is melted, bubbly, and lightly golden.

Garnish with your favorite toppings and enjoy!