Add 2 tablespoons extra-virgin olive oil - twice around the pan.
Add chicken and season with chili powder, cumin, and red onion. Brown the meat, 5 minutes.
Add taco sauce or stewed or fire roasted tomatoes.
Add black beans and corn.
Heat the mixture through, 2 to 3 minutes then season with salt, to your taste.
Coat a shallow baking dish with remaining extra-virgin olive oil, about 1 tablespoon oil.
Cut the tortillas in half or quarters to make them easy to layer with. Build lasagna in layers of meat and beans, then tortillas, then cheese. Repeat: meat, tortilla, cheese again.
Bake lasagna 12 to 15 minutes until cheese is brown and bubbly. Top with the scallions and serve.