Connect a USB drive or SD card reader to the N7 using a microUSB to USB OTG Converter Cable. Then open the "Nexus Media Importer" app and select the file. Then you are able to stream music, movies and photos and import other files from the mounting external storage, without require rooting.
The app is still work in progress. You can not save or export anything to the USB drive or SD card which comes with read-only.
After playing with this app for a hour, I find it works better and is simpler than StickMount.