COOK IT.
Preheat your Pit Boss pellet grill or smoker to 250°F.
Season chuck roast with Pit Boss GSP Rub (or garlic, salt, and pepper) then place directly on the upper rack of your grill.
In a cast iron dutch oven, add yellow onion, garlic, tomatoes, chiles, bay leaves, cumin, oregano, thyme, broth, salt, pepper, and lime juice and zest. Place cast iron on the bottom rack of your grill, under the chuck roast.
Allow the roast and consommé (broth) to cook for about 3 hours or until the internal temperature of the roast reaches 165°F.
Remove the consommé from the grill, blend until smooth and strain with a mesh cloth. Return consommé back to dutch oven.
Remove the chuck roast from the grill, cut into large pieces, and add to the dutch oven. Cover with a lid then, return it to the bottom grate of the grill. Increase the grill's temperature to 350°F and braise for 1 1/2 - 2 hours or until the beef becomes tender and shreds easily.
Remove the Dutch oven from the grill, and shred the meat with meat claws or forks.
Preheat a flat-top gas griddle or cast iron griddle to medium high heat.
Coat each tortilla with the beef fat from the Dutch oven, and place on the hot griddle. Flip after 1-2 minutes, then top with cheese and shredded beef and fold in half. Griddle the tacos until crispy on both sides.
Remove the tacos from the griddle, top with cilantro, onions, and limes, and serve with a side of broth. Enjoy!