Heat a large skillet over medium-high heat. Add the ground beef and cook, breaking it up with a spoon, until no pink remains, about 6-8 minutes. Drain off excess fat. Stir in the taco seasoning and water, reduce heat to low, and simmer until thickened, about 3-4 minutes. Remove from heat and let cool slightly.

While the beef cools, chop the lettuce into bite-sized pieces and place in your serving bowl. Dice the tomatoes and red onion, then drain and rinse the black beans. If using frozen corn, run it under warm water to thaw.

In a small bowl, whisk together the French dressing and sour cream until smooth. This creates a creamy, tangy dressing that clings to the chips without making them soggy too quickly.

Start with the chopped lettuce as your base. Scatter the black beans and corn over the top, then add the diced tomatoes and red onion. Spoon the seasoned beef evenly across the salad, then sprinkle with the shredded cheese.

Just before serving, scatter the slightly crushed Doritos over the top - you want some whole chips and some broken for variety. Drizzle the dressing over everything and toss gently at the table, or serve the dressing on the side for people to add their own.