Prep the ingredients as listed above.
Preheat the oven: Set the broiler to low.
Make the guacamole: In a bowl, mash the avocado until smooth. Mix in minced red onion, lemon juice, and cilantro. Season with salt and pepper. Refrigerate until ready to use.
Cook the beef: Heat a nonstick pan over medium heat. Add ground beef along with onion powder, cumin, garlic powder, paprika, and chili powder. Cook while breaking up the beef with a spatula. Once no longer pink, season with salt and pepper.
Assemble the nachos: Place tortilla chips on a baking sheet. Top with cooked beef, cheeses, and refried beans.
Broil: Place under the broiler until the cheese is fully melted.
Top and serve: Remove from the oven. Add lettuce, tomato, jalapeño (if using), red onion, sour cream, and guacamole. Serve with a cold beer.