Preheat your oven to 325°F. Generously season the beef chuck roast with salt, pepper, and taco seasoning. Roast it covered for about 1 hour per pound.

Shred the beef using two forks. If the meat is tough, return it to the oven covered for an additional 30 minutes.

Increase the oven temperature to 425°F, spread the beef out on a sheet pan, and roast uncovered for about 20–25 minutes until crispy.

Mash the ripe avocados, adding lime juice, orange juice, zest, salt, and pepper. Fold in red onion and cilantro.

Warm the tortillas in a skillet for about 30 seconds per side until pliable.

Assemble the tacos with guacamole, crispy beef, shredded cheese, and toppings. Serve immediately.