Android 7.0 Nougat is now Official and is available for Supported Nexus Devices, Google has already pushed Android 7.0 AOSP Source code and Developers have started working on Custom Roms.
Most of the Custom Roms, don't have Google Apps/GApps pre-installed. But you can Download GApps.zip File and Flash it manually from Custom Recovery.
Android 7.0 Nougat GApps are now available, You can Download it from below link.
Download Google Apps- GApps Android 7.0