In a large skillet, brown the ground beef over medium heat. Drain any excess fat.
Stir in taco seasoning with a splash of water. Simmer until seasoning is absorbed.
Mix Italian dressing and ranch dressing into the seasoned beef, allowing it to blend well.
Prepare the salad ingredients: shred lettuce, dice onion, and chop tomatoes.
In a large bowl, combine lettuce, tomatoes, onion, cheese, and beef mixture.
Gently fold in Doritos just before serving to keep them crunchy.
Serve immediately or set ingredients out separately so guests can build their own salads.
