Meanwhile, season the beef with the salt and pepper. Wipe out the skillet with paper towels. Heat 1 tablespoon oil over medium-high heat. Add the beef and brown on all sides, about 10 to 12 minutes. Transfer to a 4- or 5-quart slow cooker.
Heat remaining 1 tablespoon oil in the same skillet. Add onion and garlic and cook over medium heat for 4 to 5 minutes, until just starting to brown. Add the oregano, cumin, cinnamon and cloves and cook, stirring, for 1 minute. Transfer to the blender with the chiles. Add the remaining 1/2 cup of chicken broth to the skillet and bring to a boil, scraping the bottom of the skillet to release all the brown bits.
Add to the blender, along with the chipotle chile, vinegar and brown sugar. Purée until smooth and pour over the beef in the slow cooker. Add the bay leaves and cook on high setting for 4 to 5 hours or on low setting for 8 to 10 hours, until completely tender. Discard bay leaves and transfer beef to a cutting board. Skim fat from cooking liquid in slow cooker.
Use 2 forks to shred the beef into bite-sized chunks. Add the beef to the liquid and cook for another 2 to 3 minutes, gently stirring (you don't want to break up the meat too much) until the beef is hot. Season with salt, if necessary.
Serve with warm corn tortillas, chopped onions, cilantro, diced avocado and lime wedges, if desired.
Nutrition information per serving: