Preheat the oven to 350°F (175°C).
Heat 1 tablespoon olive oil in a large skillet over medium heat. Add 1 cup chopped onion and cook until softened, about 4–5 minutes.
Add 2 pounds ground beef and cook, breaking it up with a spoon, until no longer pink. Tilt the skillet and spoon off most of the rendered grease.
Stir in 1 (15 oz) can drained black beans, 1 cup corn, 1 (15 oz) can Ro-tel tomatoes (or tomatoes with chiles), 1/4 cup taco seasoning, and 1/2 cup beef broth. Simmer over medium-low heat until most liquid has evaporated, about 10–12 minutes, then remove from heat.
In a medium bowl, combine 16 oz sour cream with the 4.5 oz can green chiles until evenly mixed.
Assemble the lasagna in a 9"x13" baking dish: spread one-third of the meat mixture evenly on the bottom, then cover with a layer of tortillas. Add another third of the meat, then one-third of the shredded cheddar.
Add a second layer of tortillas, spread the sour cream–chile mixture over them, then sprinkle another third of the cheese.
Top with a final layer of tortillas, spread the remaining meat mixture, and finish with the remaining shredded cheddar.
Bake uncovered for 25 minutes, until heated through and bubbly. Let rest about 5 minutes, then top with pico de gallo, chopped cilantro, and sliced pickled jalapeños if desired. Slice and serve.
