Preheat the oven to 350°F (175°C).
In a large skillet over medium heat, cook the ground beef until browned. Drain excess fat.
Add the black beans, diced tomatoes, and taco seasoning to the skillet. Stir well and simmer for 5 minutes.
In a mixing bowl, combine the sour cream and salsa. Set aside.
In a 9x13-inch baking dish, spread a thin layer of the salsa mixture on the bottom.
Place 4 tortillas over the salsa mixture, overlapping slightly.
Spread half of the beef mixture over the tortillas, followed by a third of the cheddar cheese.
Add another layer of 4 tortillas, then half of the salsa mixture, the remaining beef mixture, and another third of the cheddar cheese.
Top with the last 4 tortillas and the remaining salsa mixture, finishing with the last third of the cheddar cheese on top.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden.
Let the lasagna cool for 5 minutes before slicing. Garnish with fresh cilantro if desired.