Whisk soy sauce, brown sugar, water, bourbon, sesame oil, and pepper; heat and divide the mixture.
Toss chicken with cornstarch and a portion of the sauce.
Sear chicken in oil until browned and cooked through, 10 min.
Sauté garlic and ginger, add remaining sauce, simmer until syrupy, 6–8 min; stir in vinegar.
Toss chicken in the glaze and serve over rice.