In a skillet over medium-high heat, add the olive oil and half the onion. Cook it until starting to soften, then add the ground beef. Cook the meat until it's totally browned, then drain the fat. Add the chili powder, paprika, cumin, crushed red pepper, salt, and pepper and stir to combine. Add the beans and hot water and stir. Reduce the heat to low and simmer while you prepare the other ingredients.
To make the pico de gallo, combine the other half of the onion with the tomato, jalapeno, cilantro, lime juice, and 1/2 teaspoon salt. Stir it together and set it aside.
Preheat oven to 375 degrees.
To build the nachos, place a layer of tortilla chips on a rimmed baking sheet. Top with a layer of the beef/bean mixture, then all but 1/4 cup of the cheddar cheese. Add another layer of chips, another layer of the beef/bean mixture, and the Monterey Jack cheese. Add a final small layer of chips, then a small layer of beef and beans, then a final sprinkling of cheddar.
Bake in the oven just until the cheese melts, about 5-10 minutes.
Sprinkle on the diced avocado and plenty of pico de gallo. Add a couple dollops of sour cream and cilantro.
Serve immediately.