In a large skillet over medium heat, cook the ground beef until browned, about 5-7 minutes.
Drain the excess fat from the skillet and stir in the taco seasoning. Cook according to packet instructions or for about 2 minutes.
Stir in the cream of chicken soup, sour cream, and drained diced tomatoes until well mixed.
In a greased 9x13-inch baking dish, layer half of the Doritos at the bottom. Spoon half of the beef mixture over the chips, then sprinkle one cup of cheddar cheese on top. Repeat with the remaining Doritos, beef mixture, and cheese.
Cover the dish with aluminum foil and bake for 20 minutes. Remove the foil and continue baking for another 10-15 minutes.
Once baked, let it cool for a few minutes and garnish with chopped green onions before serving.