In a large saucepan, bring broth and water to a simmer; keep hot. In another large saucepan, heat 2 tablespoons butter and oil over medium heat. Add mushrooms and onion; cook and stir 6-8 minutes or until tender. Add rice; cook and stir 2-3 minutes or until rice is coated.
Stir in wine and lemon juice. Reduce heat to maintain a simmer; cook and stir until wine mixture is absorbed. Add hot broth mixture, 1/2 cup at a time, cooking and stirring until broth has been absorbed after each addition, until rice is tender but firm to the bite and risotto is creamy.
Stir in chicken, cheese, parsley, salt, pepper and remaining butter; heat through. Serve immediately.