Cook chicken and onion in 2 tablespoons of butter in a large skillet over medium high heat, stirring until chicken is browned and onion is tender.
Stir in celery, mixed vegetables, mushrooms, chopped potato, 1 cup of chicken broth, white wine, parsley, pepper and bay leaf. Bring to a boil, cover and reduce heat. Simmer 15 minutes or until vegetables are tender. Discard the bay leaf.