You just gotta love North American carriers. Nexus devices are the only safe haven in the Android world where users get instant OS updates as and when Google announces them, but US carriers manage to always take away even that convenience from their consumers. On the day when Android 4.4 is expected to be officially announced, Sprint has begun rolling out the Android 4.3 update (build GJ04) for the Galaxy Nexus. Impressive, isn't it?
The Android 4.3 update isn't a major one, and includes features such as TRIM support for faster and consistent performance, always-on Wi-Fi location scanning (can be turned off from Wi-Fi settings), support for multiple new languages, improved typing, auto-complete in the dialer, and other under-the-hood tweaks.
The update's available over-the-air and should be arriving on your Spring Galaxy Nexus in the next few hours/days, and you can do a manual check for its availability from the Settings » About phone » System updates menu. There's no guarantee the Galaxy Nexus will be getting updated to Android 4.4 KitKat, but even if it does, you can be sure you'll be waiting a few months before Sprint (and other carriers) decide to start its rollout.