Place the meat and onion in a skillet over medium-high heat on the stove and cook until the meat is completely browned and the onions have softened. Drain any excess grease.
Reduce the heat to medium and add in the taco seasoning, corn, diced tomatoes, and black beans. Stir to combine well.
Cut the corn tortillas in half.
Place a layer of corn tortilla in the bottom of a well-greased 9×13 baking dish.
Top the tortillas with half of the meat mixture.
Spread the sour cream on top of the meat.
Add another layer of corn tortillas.
Place the other half of the meat on top of the tortillas.
Bake for 25 minutes.
Remove, top with the shredded cheese and chopped green onions for garnish.
