1. Season and Brown the Roast:

• Pat the boneless beef chuck roast dry with paper towels. Sprinkle it generously all over with the 1 teaspoon of salt and 1 teaspoon of pepper.
• Heat the olive oil in a large, heavy skillet over medium-high heat.
• Once the oil is hot, carefully place the seasoned chuck roast into the skillet. Brown the meat well on all sides. This searing step develops a rich, deep flavor and typically takes about 8-10 minutes total.
• Once browned, transfer the meat to the insert of a 5- or 6-quart slow cooker.

2. Deglaze Skillet and Prepare Braising Liquid for Slow Cooker:

• Pour the beer (or beef broth) into the hot skillet used for searing. Stir and scrape vigorously with a wooden spoon or spatula to loosen any flavorful browned bits (fond) from the bottom of the pan. Let this simmer for a minute.
• Pour this deglazing liquid from the skillet over the roast in the slow cooker.
• In a large bowl (or directly in the slow cooker if space allows for mixing), combine the entire undrained can of pickled jalapeno peppers (peppers and their brine), the chopped large onion, 1 teaspoon garlic powder, and 1 teaspoon chili powder.
• Pour this jalapeño-onion mixture evenly over the meat in the slow cooker.

3. Slow Cook the Chuck Roast:

• Cover the slow cooker securely with its lid.
• Cook on the LOW setting for 6-8 hours, or until the beef is exceptionally tender and easily shreds with a fork.

4. Shred Roast, Skim Juices, and Combine:

• Once the roast is fall-apart tender, carefully remove it from the slow cooker using tongs or large forks. Place it on a large cutting board or platter, leaving the cooking liquid in the slow cooker.
• Strain the cooking juices from the slow cooker through a fine-mesh sieve into a bowl or fat separator.
• From the strained solids, you can reserve the cooked onions and jalapeño peppers (which will be very soft and have imparted their flavor) to add back to the meat if desired. Discard any unwanted large pieces.
• Allow the strained cooking juices to sit for a few minutes, then carefully skim off as much visible fat from the surface as possible using a fat separator or a large, shallow spoon.
• Reserve 2 cups of these skimmed, flavorful cooking juices. Discard any remaining excess juices.
• Using two forks, shred the cooked chuck roast. Discard any large pieces of fat or gristle from the meat.
• Return the shredded beef to the slow cooker. Add back the reserved cooked vegetables (onions and jalapeños) and the reserved 2 cups of skimmed cooking juices.
• Stir everything together gently to combine. Cover and let it heat through on LOW or WARM setting for another 15-30 minutes, allowing the shredded beef to absorb the flavorful juices.

5. Assemble and Serve Tacos:

• While the shredded beef mixture heats through, warm your corn tortillas according to your preferred method (e.g., briefly in a dry skillet, wrapped in damp paper towels in the microwave, or wrapped in foil in a low oven).
• To serve, spoon a generous portion of the warm, spicy Chuck Roast Taco filling into each warmed tortilla.
• Top with your desired optional toppings, such as crumbled Cotija cheese, a squeeze of fresh lime juice from lime wedges, fresh cilantro leaves, sliced radishes, and/or a dollop of sour cream.
• Serve immediately and enjoy your incredibly flavorful homemade tacos!