Last week Google has announced Android 4.3, the latest version of its mobile platform. At the time of launch Google has announced that Android 4.3 will hit other Galaxy phone too very soo, we had already shared a trick to update your Nexus device but that requires flashing your device.
If you are looking for a simple trick then here is it, navigate to Setting -> Apps, select All and look for Google Services Framework, tap on it and click on Clear Data, you will get a warning, just ignore it and move ahead.
Once done go to Settings and scroll down About Phone and select System Update, it will show last checked in 1970 or so, now check again and you will get update.
This method has been checked on Nexus 4 but it should work on other Nexus devices too.