Season the Pork: Trim excess fat and season the pork chunks with salt and pepper.
Sear the Pork: Heat oil in a skillet and sear the pork on all sides until browned (optional).
Combine Ingredients: Place the pork in the slow cooker. Add onion, garlic, chipotle peppers, cumin, smoked paprika, oregano, brown sugar, chicken broth, and apple cider vinegar.
Slow Cook: Cover and cook on low for 8-10 hours or on high for 5-6 hours, until the pork is tender.
Shred and Serve: Remove the pork, shred it, and mix it back into the sauce. Serve warm.