Preheat oven to 325°F. Lightly grease a 13x9x2-inch baking dish.
In a large bowl, combine soup and next 7 ingredients. Stir in vegetables, onion, mushroom, potatoes and chicken. Spoon mixture into prepared baking dish. Evenly sprinkle over the cheddar cheese. Set aside while you make the crust.
CRUST 2½ cups pancake mix (I used Krusteaz Whole Wheat mix) 1/3 cup vegetable shortening 1/2 cup cold buttermilk 1 egg, beaten
Dump the pancake mix into a large mixing bowl. Add the shortening. Cut with a pastry knife or two butter knives until blended and crumbly. Add the buttermilk and egg and lightly blend, not overdoing it. Add more buttermilk a little at a time until the batter is very thick but pourable.
Evenly, slowly, pour the batter over the pot pie mixture.
Bake for about 40 minutes or until the crust is golden brown.
Remove from over and let set about 5 minutes before serving.