Android 4.2.2 for Verizon's Samsung GALAXY Nexus leaks
should not be flashed over another ROM. You need to be running a stock version of 4.1.1 (JRO03O). Your phone also should be rooted with custom recovery, or be able to temporarily boot a custom recovery. You can grab everything you need from the sourcelink. But be warned! Remember what you mom said if you go ahead and flash this update. She said you would need glasses and grow pimples on your tongue. Or was that for something else? Anyway, you need to make sure that you know what you are doing here or else your Samsung GALAXY Nexus becomes a stock Android paperweight with no warranty and no recourse.
source: XDA, DroidLife via AndroidCentral