Grease the crock of your slow cooker liberally.  Lay sliced onions in the bottom of the crock. Season chicken with salt and pepper and lay on top of the onions.

Mix barbecue sauce, brown sugar, water, and Worcestershire sauce and pour over chicken.

Cover and cook on high for three to four hours.

When chicken is nice and soft, remove from the slow cooker and shred with two forks.

Fry (or bake, works equally well) French fries until nice and crispy.

In a serving dish, arrange the French fries. Top with shredded chicken and onions and continue to layer with your favorite toppings. Drizzle generously with spicy mayo or garlic aioli.