Preheat your oven to 350°F. Trust me, do it first—you’ll forget later.
In a large skillet, cook the ground beef and diced onion over medium heat until the beef is no longer pink. Drain the grease like a pro.
Add taco seasoning and water. Stir it up and let it simmer for about 5 minutes until thickened.
Turn off the heat, then mix in the Rotel, cream of mushroom soup, and sour cream. Stir until everything looks suspiciously delicious.
In a 9x13 baking dish, sprinkle a generous layer of crushed Doritos (but don’t pulverize them—we want crunch, not dust).
Spread half the beef mixture over the chips. Add a layer of shredded cheese. Repeat: more Doritos, more beef, more cheese.
Bake uncovered for 20-25 minutes, or until bubbly and golden like it’s trying to impress someone.
Let it rest for a few minutes (you’ll be tempted, but the roof of your mouth will thank you). Then dive in!