Preheat oven to 350°F (175°C).
In a large skillet, cook ground beef over medium heat until browned. Drain excess fat.
Add taco seasoning and ½ cup water. Simmer 3–4 minutes until thickened.
In a bowl, mix sour cream and Rotel. Add the cooked beef and stir to combine.
Crush Doritos lightly into bite-sized pieces.
In a greased 9x13 baking dish, layer half the Doritos, the beef mixture, 1 cup of cheese, then remaining Doritos and cheese.
Cover loosely with foil and bake for 20 minutes. Remove foil and bake another 5–10 minutes until bubbly.
Let rest for 5 minutes before serving. Top with sour cream, green onions, or jalapeños if desired.