Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Season the chuck roast generously with salt and black pepper. Once the oil shimmers, carefully place the roast in the skillet and sear for about 4-5 minutes on each side until a rich golden-brown crust forms.

Transfer the seared roast to a slow cooker. In the same skillet, add 1 sliced onion and sauté for 2-3 minutes until softened. Stir in 4-5 minced garlic cloves before transferring everything into the slow cooker. Pour in 1 cup of beef broth and sprinkle with chili powder, cumin, smoked paprika, oregano, and additional salt and pepper.

Cover the slow cooker and set it to low for 7-8 hours or high for 4-5 hours. Avoid opening the lid frequently to maintain steam.

Once cooked, remove the roast and shred it into bite-sized pieces. Return the shredded beef to the juices in the slow cooker, mixing well. Squeeze in the juice of one lime.

Warm your tortillas according to package instructions until soft.

Assemble the tacos by filling each tortilla with shredded beef and topping with desired ingredients like cheese, cilantro, onions, jalapeños, sour cream, and salsa.