Preheat oven to 350°F. Add the condensed soup and mustard to a bowl. Add the chicken and veggies and give it a good stir.
Transfer the mixture to a 9-inch baking dish. Whisk the milk with egg and oil. Add the Bisquick mix and whisk until you have a smooth batter.
Pour the batter over the filling. Bake the chicken pot pie for 30 minutes.