Prepare the chuck roast. Add oil to a skillet over medium-high heat. Season beef chuck with sea salt and pepper and add to skillet to brown on both sides, roughly 5 minutes per side.
Add browned chuck roast to Instant Pot® and cover with beef broth and spices. Switch Instant Pot® to ‘pressure cook’ and set to 80 minutes. Place lid on the pot and seal. Make sure the vent is set to a sealed position.
Carefully open the vent and let steam release for 10 minutes.
Transfer the roast to a cutting board and use a fork and knife to pull meat apart. Set aside.
Add tortilla chips to a large baking tray lined with parchment paper. Sprinkle with cheese, beans, shredded beef, pico de gallo, and red onion.
Turn oven on broil and add baking tray to the oven. Broil for 5 minutes, or until cheese is melted and chips are slightly browned.
Remove tray from oven and add chopped cilantro, radishes, and avocado. Devour!