Put chicken in slow cooker and cover with broth. (Can substitute with 14 oz. water and a bouillon cube.)
Cook on low in slow cooker between 4-5 hours. (It will be plenty ready, you can even start with frozen chicken!)
Remove chicken from crockpot when tender.
In saucepan, mix two cups of broth and two packages of gravy mix. Heat over medium heat, stirring constantly, until it thicken (about two minutes.)
Serve chicken over mashed potatoes, and top with gravy.