Place the sauce ingredients in a bowl and stir to combine. Place the chicken in the slow cooker and pour the sauce over. Cook on LOW for 4-6 hours or HIGH for 3-4 hours.
Carefully pour the liquid from the slow cooker into a saucepan and bring it to a simmer. Pour in the cornstarch slurry, whisking continually until the sauce is thickened. Pour the sauce back over the chicken. Serve with rice or mashed potatoes and your choice of veggies.