Preheat your oven to 375°F (190°C). Line a large rimmed baking sheet with parchment paper or aluminum foil for easy cleanup.
In a large skillet over medium-high heat, brown the ground beef, breaking it into small crumbles as it cooks. When the beef is about halfway cooked (after about 3-4 minutes), add the diced onion and continue cooking until the onion becomes translucent. Add the minced garlic and cook for 30 seconds until fragrant.
Reduce heat to medium and add the taco seasoning, tomato paste, and water or broth to the skillet. Stir well to combine all ingredients. Simmer for 3-5 minutes until the mixture thickens and most of the liquid has evaporated.
Spread half of the tortilla chips in an even layer on the prepared baking sheet. Dollop half of the refried beans in small amounts over the chips. Sprinkle with half of the beef mixture and one-third of the cheese.
Add the remaining chips as a second layer. Top with the remaining refried beans, beef mixture, and most of the remaining cheese, saving some cheese for the final topping.
Bake in the preheated oven for 10-12 minutes, or until the cheese is completely melted and beginning to bubble around the edges. For extra crispiness, broil for the final 1-2 minutes, but watch carefully to prevent burning.
Remove the nachos from the oven and immediately top with diced tomatoes, jalapeño slices, black olives, green onions, and cilantro. Finish with the remaining cheese, which will melt slightly from the residual heat.
Serve immediately with sour cream, salsa, and avocado on the side or directly on top of the nachos.