Prepare the Shredded Beef:
Season the beef chuck roast with salt and pepper. Heat olive oil in a skillet over medium-high heat and sear the roast on all sides until browned.
Place the beef in a slow cooker or Dutch oven. Add onion, garlic, beef broth, tomato sauce, taco seasoning, lime juice, cumin, smoked paprika, and chili powder. Cook on low for 8 hours or until the beef is tender and easy to shred.
Remove the beef from the cooker and shred it with two forks. Return it to the sauce and stir well.
Assemble the Nachos:
Preheat the oven to 375°F (190°C). Line a baking sheet with parchment paper or foil.
Spread a layer of tortilla chips on the baking sheet. Top with shredded beef, black beans, corn, and shredded cheese. Add another layer of chips and repeat.
Bake the Nachos:
Place the loaded baking sheet in the oven and bake for 8–10 minutes or until the cheese is melted and bubbly.
Add Fresh Toppings:
Remove the nachos from the oven and top with diced tomatoes, pickled jalapeños, red onion, and fresh cilantro.
Serve:
Serve the nachos hot with guacamole, sour cream, and salsa on the side.