Place chicken breasts in slow cooker and pour sauce on top. Cook on low for 4-5 hours.
Remove chicken from slow cooker and shred, set aside.
In a small bowl, combine 3 tablespoons of water and corn flour. Place liquid from slow cooker into a saucepan and bring to a boil. While stirring, add corn flour mixture and stir until thickened. Let boil for 1 minute.