OMG this was deeeelicious! Halved the recipe and cooked it an 8×8 and turned out AMAZING.

Heat the Oil: In a large skillet over medium-high heat, heat the olive oil.
Sauté the Aromatics: Add the chopped onion and minced garlic to the pan. Sauté them for 3-4 minutes, or until the onion becomes translucent and fragrant.
Brown the Beef: Add the ground beef to the skillet and break it up with a spoon as it cooks. Continue cooking for 5-7 minutes, or until the beef is fully browned.
Season and Simmer: Stir in the taco seasoning and ½ cup of water (adjust the water amount as needed). Let it simmer for 2-3 minutes, allowing the water to reduce slightly and the seasoning to coat the beef.
Assemble the Lasagna (10 minutes):

Layer 1: Salsa and Tortillas: In a 9×13 inch baking dish, spread a thin layer of salsa on the bottom. Top it with four tortillas, overlapping slightly if necessary.
Layer 2: Beef, Beans, and Cheese: Spread a third of the cooked beef mixture over the tortillas. Then, layer with a third of the black beans, green chiles (if using), salsa, and shredded cheese.
Repeat and Top (5 minutes):

Repeat the Layers: Repeat step 3 two more times, creating a total of three layers with tortillas, beef mixture, beans, salsa, and cheese.
Cheese and Sour Cream: Finish the lasagna with a final layer of shredded cheese on top. Dollop spoonfuls of sour cream evenly over the cheese.
Bake and Enjoy (25-35 minutes):

Covered Bake (25 minutes): Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
Uncovered Bake (10-15 minutes): Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly on top.
Cool and Serve (10 minutes): Let the lasagna cool for 10 minutes before slicing and serving. This allows it to set and makes cutting into clean portions easier.