Preheat the oven to 375°F (190°C).
Heat olive oil in a large skillet over medium heat.
Add chopped onion and cook for 3-4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook, breaking it apart with a spoon until browned and cooked through, about 6-8 minutes.
Drain excess fat from the skillet.
Stir in taco seasoning mix and water. Simmer for 3-4 minutes until the sauce thickens and coats the beef evenly.
Spread tortilla chips evenly on a large oven-safe baking sheet or dish.
Evenly distribute the seasoned ground beef over the tortilla chips.
Sprinkle shredded cheddar and Monterey Jack cheeses evenly over the beef and chips.
Bake in the preheated oven for 8-10 minutes until the cheese is melted and bubbly.
Remove from oven and top with diced tomatoes, sliced black olives, jalapeños, and chopped green onions.
Serve immediately with sour cream and guacamole on the side.