Heat a large skillet over medium-high heat and add 2 tablespoons of olive oil. Season the chuck roast generously with salt and black pepper. Sear for about 4-5 minutes on each side until brown.

Transfer the roast to the slow cooker, add one sliced yellow onion and four minced garlic cloves, then pour in 1 cup of beef broth, followed by 2 tablespoons of chili powder and cumin.

Sprinkle in smoked paprika, oregano, and adjust salt and black pepper to taste. Mix well to coat the roast evenly.

Cover and set the slow cooker on low heat for 7-8 hours or high for 4-5 hours until fork-tender.

After cooking, shred the beef into pieces and return it to the slow cooker to soak in the juices. Squeeze in the juice of one lime.

Warm the tortillas according to package instructions and assemble the tacos with shredded beef and toppings.