Chop 1 large onion and place it into the bottom of the slow cooker.
Combine 1 Tbsp salt, 1 tsp pepper, and 1 tsp paprika and generously sprinkle the pork roast. Massage the roast to rub the seasoning into the meat. Place meat over the onions.
For the marinade, combine: 1 cup chicken broth, 1 cup BBQ sauce, 1 Tbsp liquid smoke, 2 Tbsp Worcestershire sauce, 2 Tbsp brown sugar, and 3 pressed garlic cloves. Stir to combine. Pour the marinade over the pork.
Cover and set on low for 8 hours for 2 smaller roasts or 8-10 hours for a single large roast. It's ready when easily pulled apart with forks. Remove the meat to a large bowl and remove any fat. Shred with forks. Pour any drippings from the crockpot over the meat to taste then brush meat with warm barbecue sauce to serve.
