As a nexus user, you must be aware that you can download the factory images for each android update from the Google developers portal. However, things are now much easier if you are “Serial Flasher” (thanks to Droid-Life) as you can now download the OTA in .Zip formats too for sideload, that too from official sources. It’s true that we have seen OTA .zips being distributed by various android hubs like Android Central in the past but now you won’t need to go anywhere, which makes things better as OTA’s are always the best way to go for an update in case of most users.
Off-course one can always get the complete factory image and flash it in case you need to or prefer it, but that requires a greater effort as you need an Unlocked Bootloader (voids warranty in most cases) and your device get’s completely wiped, in which case you need to take a complete backup prior to applying every update. Now most people may be wondering why Google didn’t take this route earlier, so we went ahead and contacted them which resulted in a response saying – “Due to monthly security updates and at times two in a month we considered the nexus user’s difficulties”. It is more than clear now that Google cares about it’s users, more than it ever did and we wish other OEM’s follow their lead.
You can browse the source link to find the above mentioned OTA (.zip) links for your beloved Nexus device.