In a small skillet, cook beef over medium heat until no longer pink; drain. Stir in water and taco seasoning. Bring to a boil; cook and stir for 2 minutes. Cool slightly., In a small bowl, mash avocados with onion, garlic and lemon juice. In a 3-qt. glass bowl, layer with beef, avocado mixture, lettuce, olives, tomatoes, cucumber, green onions, cheese, salsa and sour cream. Serve immediately with chips.