Begin by trimming any excess fat from the beef chuck roast. Pat it dry with paper towels, then season it generously with salt and pepper on both sides.

In a large skillet over medium-high heat, add a splash of oil. Once hot, add the beef roast and sear it for about 3-4 minutes on each side until it’s nicely browned.

In your slow cooker or a large pot, layer the chopped onion and minced garlic at the bottom. Place the seared beef on top, then add the diced tomatoes (with their juices), diced green chiles, chili powder, cumin, oregano, and beef broth.

If using a slow cooker, set it to low and cook for 8 hours. Alternatively, if cooking on the stovetop, bring to a boil, then reduce heat to low, cover, and simmer for about 3-4 hours, or until the beef is very tender.

Once cooked, remove the beef from the pot. Let it cool for a few minutes, then use two forks to shred the meat into bite-sized pieces.

Return the shredded beef to the cooking liquid and stir to combine everything. Allow it to simmer for another 10-15 minutes for the flavors to meld.

Garnish with fresh cilantro, and serve the Mexican shredded beef in tacos, burritos, or over rice.