Heat a tablespoon of olive oil in a large skillet over medium-high heat. Season the chuck roast with salt and pepper, then sear for 4-5 minutes on each side until browned.

Transfer the seared chuck roast to the slow cooker. Layer the sliced onion and minced garlic around it, then pour in the beef broth. Sprinkle chili powder and cumin on top.

Cover the slow cooker and cook on low for 7-8 hours or high for 4-5 hours, until the meat is tender.

Remove the roast and shred it on a cutting board using two forks, then mix it back into the juices.

Squeeze lime juice over the shredded meat and stir well.

Warm the tortillas and fill each with the shredded beef mixture, adding your favorite toppings.