Season the beef: Pat the chuck roast dry.
Mix salt, pepper, cumin, chili powder, smoked paprika, and oregano. Rub the spice mix all over the beef.
Optional sear: Heat oil in a skillet over medium-high. Sear the roast 2–3 minutes per side until browned.
This adds flavor but isn’t required if you’re short on time.
Build the base: Add onions and garlic to the slow cooker. Stir in diced tomatoes, tomato paste, chipotle with adobo sauce, and beef broth. Nestle in the bay leaves.
Add the beef: Place the roast on top of the mixture.
Spoon some sauce over the meat.
Cook low and slow: Cover and cook on LOW for 8–10 hours or HIGH for 4–5 hours, until the beef shreds easily with two forks.
Shred and finish: Remove the beef to a cutting board. Discard bay leaves. Shred the beef, then return it to the slow cooker with its juices.
Brighten the flavor: Stir in lime juice and apple cider vinegar.
Taste and adjust salt, lime, or chipotle as needed.
Serve: Spoon the beef into warm tortillas and top with onion, cilantro, salsa, and avocado. Or use it for bowls, salads, or quesadillas.