Prepare the Beef: Pat your 3-4 pound beef chuck roast dry with paper towels. Season it generously all over with 1 tablespoon of salt and 1 teaspoon of black pepper. You can also quickly sear the beef in a hot pan for a few minutes on each side until browned (optional, but adds deeper flavor).

Season the Broth: In your slow cooker, pour in 3 cups of beef broth. Add the remaining spices: 2 tablespoons chili powder, 1 tablespoon ground cumin, 1 teaspoon garlic powder, 1 teaspoon onion powder, and 1 teaspoon dried oregano. Stir these ingredients well to combine.

Add the Beef to the Slow Cooker: Carefully place the seasoned chuck roast into the slow cooker, ensuring it’s mostly submerged in the seasoned beef broth.

Cook Low and Slow: Cover the slow cooker and cook on the LOW setting for 6-8 hours, or on HIGH for 3-4 hours, until the beef is incredibly tender and easily pulls apart with a fork.

Shred the Beef: Once cooked, carefully remove the beef from the slow cooker and place it on a large cutting board or in a shallow dish. Using two forks, shred the beef into bite-sized pieces. It should fall apart very easily.

Combine with Juices: Return the shredded beef to the slow cooker with the cooking liquid. Stir it to ensure all the beef is coated in those flavorful juices. Keep the beef on the "warm" setting if serving immediately, or transfer to a serving bowl.

Warm the Taco Shells: Preheat your oven to 325°F (160°C). Place the hard taco shells directly on an oven rack and bake for 5-7 minutes, or until lightly crisp and warm. Alternatively, you can warm them briefly in a microwave.

Arrange the Toppings: Lay out all your fresh toppings in individual bowls: shredded lettuce, diced tomatoes, shredded cheddar cheese, sour cream, salsa, fresh cilantro, and lime wedges.

Serve the Beef: Place the warm, shredded beef mixture in a central serving dish, along with tongs or a large spoon.

Build Your Tacos: Each person can take a warm hard shell, spoon in a generous amount of the juicy shredded beef, and then add their favorite toppings. Don't forget a squeeze of fresh lime juice at the end—it really brightens the whole taco!