Solution to disable OTA update (kitkat) WITHOUT ROOTING.
Well, as the title says, wish I had figured it out before unlocking the bootloader. Here's what to do:
When the nagging OTA update shows up to update to kitkat, click download.
After download is complete it will ask to install and nag you to install it.
When you see this, turn off the phone.
Once off, boot into recovery (vol down + power key pressed for 3 seconds then release)
Scroll to recovery by using vol down and then select recovery by vol up.
Scroll to clear cache by vol down and then select with power key.
Select power key again to move back into recovery.
Select power key again to reboot.
Once you reboot go into Settings -> About phone -> System Update
Install the update.
Watch it install and then fail.
Laugh in an evil manner.
Phone will automatically log you back in and you will see a message such as update failed.
The annoying update ota nag will be gone forever.