Preheat oven to 325°F.
Combine oregano, chili powder, cumin, paprika, salt and pepper in a small bowl. Sprinkle seasoning over meat and use your hand to rub it onto the meat.
Combine oregano, chili powder, cumin, paprika, salt and pepper in a small bowl. Sprinkle seasoning over meat and use your hand to rub it onto the meat.
Heat the oil in a heavy bottom pot or Dutch oven over high heat. Sear the meat on both sides. Once the meat is seared, add garlic, onion, and jalapeno and cook for 1-2 minutes.
Add orange juice, lime juice, and stock (or water), scraping the bottom of the pot to deglaze it. Cover and place in oven for 2½-3 hours or until the beef is tender enough to shred. Alternatively, you can place the meat in a slow cooker after searing it. Add the rest of the ingredients, cover and cook on low for 6 hours or on high for 4 hours.
Remove beef from pot and shred using 2 forks. Once shredded, place meat back in juices to keep it from drying out.
To assemble tacos, spread shredded beef in the middle of a warm tortilla. Top with sliced avocado, cilantro, chopped onion, lime, and hot sauce.
