Mix first 8 ingredients in bowl. Add chicken. Cover; refrigerate 30 minutes.
Cook rice, cumin in 3 cups water according to package directions in pan; add peas last 5 minutes. Reserve.
Simmer chicken with marinade in second pan 12 minutes. Add cornstarch; cook to thicken, 2 minutes. Add sour cream; heat (dont boil). Serve over rice.