From https://www.recipetineats.com/mexican-shredded-beef-and-tacos/

Ingredients

Spice mix

• 1.5 tablespoons chipotle powder
• 1 tablespoon paprika
• 1 tablespoon dried oregano
• 1 teaspoon All Spice powder
• 1 teaspoon coriander powder
• 2 teaspoons onion or garlic powder
• 1 teaspoon each of salt and pepper

Beef

• 1-2 tablespoons of olive oil
• 1.5kg beef chuck or brisket (not too fatty though)
• 5 garlic cloves, minced
• 1 onion
• 185ml orange juice
• 2 tablespoons of lime juice
• 400g can chopped tomatoes
• 500ml beef or chick stock
• 125ml water
• Salt and pepper

Method

1. Combine the Spice Mix ingredients in a bowl. Sprinkle 4 teaspoons over the beef and pat so it sticks.
2. Heat the olive oil in a large heavy based pot over high heat. Add the beef (in batches if necessary) and brown well on all sides. Remove to a plate.
3. Turn the stove down to medium. If the pot looks dry, add more olive oil.
4. Add the garlic and onion and cook for 3 minutes until soft.
5. Add the orange juice and lime juice, and scrape the bottom of the pot so the brown bits mix into the liquid.
6. Add tomato, beef stock, water and remaining spice mix. Mix, then return beef into pot.
7. Put the lid on, bring to a simmer then turn the stove down so it is bubbling gently, not rapidly.
8. Cook for 2 hours, then remove lid and simmer for another 30 minutes until beef is tender enough to shred.
9. Remove the beef from sauce, shred with 2 forks.
10. Leave the sauce to simmer with the lid off for 10 to 15 minutes to reduce and thicken to your taste. Adjust salt to taste. Optional: puree with stick blender to make it smooth.
11. Toss beef back into the sauce (can reserve some Sauce for drizzling on tacos if you want, there's plenty).
12. Transfer beef into large dish and serve. See notes for suggestions.

To make tacos, serve the beef with warmed small tortillas, avocado slices, Pico de Gallo, shredded cheese, sour cream, lime wedges and extra cilantro/coriander leaves.