Preheat your oven to 350°F (175°C).
In a large skillet over medium heat, add the olive oil. Once hot, add the diced onion and sauté for 2-3 minutes until translucent.
Add the minced garlic and ground beef to the skillet. Cook until the beef is browned, breaking it up with a spatula, about 5-7 minutes.
Drain any excess fat from the skillet. Stir in the taco seasoning and the diced green chilies. Add ¼ cup of water and let it simmer for another 5 minutes until well combined.
On a baking sheet, spread a layer of tortilla chips evenly. Spoon the seasoned beef mixture over the chips. Sprinkle shredded cheddar cheese generously over the top, covering all the beef.
If desired, add sliced jalapeños on top of the cheese.
Bake in the preheated oven for 10-12 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for a minute. Serve the nachos hot, topped with sour cream, guacamole, salsa, and fresh cilantro if using.