This comes under the heading of "boy do I feel stupid". I just got off the phone with Nexus tech support. The problem was not that the jack was not working, but that when you switch from speakers to headphones or external speakers the volume controls change. I guess there are separate controls depending on how you are listening. So after being advised to, I turned up the volume and yes I could hear. Besides feeling "stupid" I also felt happy since Walmart's return policy on tablets is only 15 days.
So happy ending. Now, on to bigger and better things.