I here a lot of people talking about the Nyko Play Pad Pro. Well I prefer to use the Xbox 360 controller, which is completely possible with the Shield.

All you need to use is a dongle that has a USB female port on one end, and a micro USB male connector on the other as shown in the pictures to the left.
You can get this from most electronics stores. Mine came with a cheap tablet I got from Big Lots. That tablet sucked by the way, but it was only $50 so what could I expect. Anyway I digress.
You can get this from most electronics stores. Mine came with a cheap tablet I got from Big Lots. That tablet sucked by the way, but it was only $50 so what could I expect. Anyway I digress.