Greg,
Per our conversation earlier, I think your ADS-B was working. The NEXRAD will only show on the Weather Mode. If the Metars, TAFs, Winds and such were there and update (not left over from an online update), it is connected. We currently do not support showing the NEXRAD on the Sectional or Charts, only our base map.
Try going to the Weather Mode next time and see if you see some NEXRAD. You can also touch and hold the screen in order to choose "Animate NEXRAD" loop. I hope this helps.