Preheat the oven to 350°F.

Cook the ground beef and diced onion in a large skillet, breaking up the meat, until no longer pink.

Add the taco seasoning, Rotel, black beans, refried beans, and enchilada sauce. Cook over medium heat for a few minutes until warm.

Spread a small amount of the mixture in the bottom of a 9x13 inch casserole dish.

Cut the tortillas in half, then cut two of the halves in half again.

Arrange two tortilla halves in the bottom of the pan with the rounded edges toward the center. Fill the top and bottom gaps with a quarter piece of tortilla.

Top with one-third of the meat mixture and one-third of the cheese.

Repeat the tortilla, meat, and cheese layers for a second layer.

For the third layer, use four tortilla halves, then top with the remaining meat mixture and the rest of the cheese.

Cover with foil and bake for 30 minutes. Remove foil and broil for a few minutes until the cheese is bubbly.

Remove from the oven, top with sliced green onions, and let stand a few minutes before cutting and serving.