Sam,
I think your going to need to pick up an external GPS receiver for the Nexus. GPS quality has been an issue with the nexus. We are working on some interconnecting of tablets, devices, etc for the future but it's not support and the multiple android devices could play into it.
The Dual XGPS 160 is a very solid performer for both Android and Apple. We offer it on our webstore for $149. We also have the Dual 170 ADS-B, and I think you'd really like it if you are wanting to move to an ADS-B receiver. Keep in mind a receiver is going to give you GPS and Weather, but very limited Traffic, unless you already have ADS-B out.
The SkyGuardTWX unit is a Transciever, so you'd be getting Full Weather, Traffic and GPS. Since the SkyuGuard is
Wi-Fi, it would share the GPS signal with both your iFly and Nexus. The Dual is bluetooth and will only work with your Android, not the iFly. The SkyGuard would probably be your best route if your interested in the most traffic and the ability to use it on both the iFly and Android. Just a thought.
Feel free to contact me if you want to discuss ADS=B options we offer in more detail. Have a great week.