Pat the beef brisket dry with paper towels and trim away any thick, hard pieces of fat, leaving a thin layer for flavor.

In a small bowl, combine the kosher salt, freshly ground black pepper, ground cumin, chili powder, smoked paprika, garlic powder, onion powder, and dried oregano, stirring until evenly mixed.

Rub the spice mixture generously all over the brisket, pressing it into the surface so it adheres well on all sides.

Heat the olive oil in a large heavy-bottomed pot or Dutch oven over medium-high heat until shimmering.

Sear the brisket for 3–4 minutes per side, turning with tongs, until a deep brown crust forms on all surfaces.

Reduce the heat to medium and add the minced garlic to the pot, stirring for about 30 seconds until fragrant, being careful not to burn it.

Pour in the beef broth and tomato sauce, then add the fresh lime juice and brown sugar, stirring to combine and scraping up any browned bits from the bottom of the pot.

Return the brisket to the pot if you removed it, nestling it into the liquid so the bottom is submerged and the top is still slightly exposed.

Bring the liquid just to a gentle simmer, then cover the pot with a tight-fitting lid and reduce the heat to low.

Cook the brisket on low heat for 3.5 to 4 hours, turning once or twice during cooking, until the meat is very tender and easily shreds with a fork.

While the brisket cooks, prepare the corn salsa by placing the corn kernels, diced tomatoes, finely diced red onion, and chopped fresh cilantro into a mixing bowl.

Drizzle the corn, tomato, onion, and cilantro mixture with the olive oil for corn salsa and the fresh lime juice for corn salsa, then sprinkle with the kosher salt for corn salsa and ground black pepper for corn salsa.

Toss the corn salsa gently until everything is evenly coated and well combined, then cover and refrigerate until ready to serve to allow the flavors to meld.

Once the brisket is fork-tender, transfer it to a large cutting board and let it rest for about 10 minutes so the juices redistribute.

While the brisket rests, skim any excess fat from the surface of the cooking liquid in the pot and simmer the liquid for 5–10 minutes over medium heat to slightly thicken if desired.

Using two forks, shred the rested brisket into bite-sized pieces, discarding any remaining large pieces of fat.

Return the shredded brisket to the pot with the reduced cooking liquid, stirring to coat the meat evenly in the flavorful sauce, and keep warm over low heat.

Warm the corn or flour tortillas in a dry skillet over medium heat for 20–30 seconds per side, or until soft and pliable, then stack them in a clean kitchen towel to keep warm.

To assemble the tacos, place a generous spoonful of the saucy shredded brisket down the center of each warm tortilla.

Top the brisket with a scoop of the chilled corn salsa, allowing some of the juices to drip over the meat for extra brightness.

Sprinkle each taco with a little crumbled queso fresco or feta and add a small dollop of sour cream over the top.

Serve the brisket tacos immediately with lime wedges on the side, encouraging diners to squeeze fresh lime juice over their tacos just before eating.