Skin, halve lengthwise, and bone chicken breasts.
Cut chicken breasts into 1-inch pieces; set aside.
In wok melt butter or margarine over medium-high heat.
Stir-fry mushrooms and onions in butter about 2 minutes or till soft.
Add chicken pieces and stir-fry about 5 minutes or till chicken is done.
Blend chicken broth and flour; add to chicken mixture.
Cook and stir till thickened and bubbly; cook and stir 1 minute longer.
Stir in grapes and wine; heat through.
Serve at once over rice.