Brown chicken breasts in a skillet until golden on both sides. Remove and cut into julienne strips.
Combine green pepper, onion, mushrooms, water chestnuts, 1 1/2 cups water, bouillon, soy sauce, cayenne, ginger, and garlic powder. Bring whole mixture to a boil.
Combine cornstarch and 1 cup water to make a smooth paste. Add to sauce and stir until thickened and clear. Add chicken, pimento, and cashews. Cook until heated through. Serve over steamed rice.