I understand your eagerness. I had been mashing my update button for several days after the OTA update was announced. Evidently these things roll out over the course of weeks, which is not necessarily what you would expect if Windows or Apple o/s updates are your frame of reference.
I was able to "trick" my nexus into updating, by clearing the data from the Google Data Services Framework. That seems to work for some people. Unlocking and flashing is an option that some power users take--particularlly those with LTE phones where there is no OTA yet.
I just cleared the data again, forced-stop, and checked for update again -- and it successfully checked and says I'm still up-to-date with my 4.0.1 Android.
I was able to "trick" my nexus into updating, by clearing the data from the Google Data Services Framework. That seems to work for some people. Unlocking and flashing is an option that some power users take--particularlly those with LTE phones where there is no OTA yet.