In a small bowl, place cocoa and all spices. Season with salt and pepper to taste. Rub the mixture all over the pork shoulder, then transfer it to a 5- or 6-quart slow cooker. Add chicken broth to crock and cook on high for 4 hours or low for 6 hours.
Once the pulled pork is done, use two forks to pull apart the pork while it’s still sitting in the slow cooker. Leave the pulled pork in the juices in the slow cooker and set to warm for 20-30 minutes. This will give it time to absorb more flavor.
To serve, fill each leaf of lettuce with crunchy broccoli slaw and top with pulled pork.