Preheat oven to 375°F (190°C).

Brown ground meat and chopped onion in a skillet over medium heat. Drain off any excess grease.

Stir in tomato sauce, 1 can of water, taco seasoning mix, and sliced olives. Simmer for 5 minutes.

Unroll crescent rolls and press them into a long oblong pan to form a crust.

Sprinkle half of the crushed corn chips over the bottom crust.

Spread the meat mixture evenly over the corn chips.

Spread sour cream over the meat mixture.

Sprinkle shredded cheese over the sour cream.

Top with the remaining crushed corn chips.

Bake in the preheated oven for 20 to 25 minutes, or until the crust is golden brown and the cheese is melted and bubbly.

Remove from oven and let cool slightly before cutting into squares.

Serve each square topped with shredded lettuce, tomato slices, and avocado slices.