I'm making skillet cornbread and just realized I don't have baking powder -- can I sub BISQUICK in place of flour, baking powder and baking s

Make your own in a jiffy by combining 2 parts cream of tartar with 1 part baking soda. So if you need a tablespoon of baking powder just use 2 teaspoons of cream of tartar with 1 teaspoon baking soda.

Just use a recipe for Bisquick Cornbread.
http://thekrazycouponlady.com/at-home/bisquick-cornbread/

Although I think that recipe is a bit shy on cornmeal.

remember- google is your friend
https://www.google.com/webhp?hl=en#hl=en&q=baking+powder+substitute

You probably could, although I don't like the taste of Bisquick and would think it would adversely affect the flavor of the cornbread.