Having the cdma cousin, you ought get the battery life you are expecting. However GNex radios are iffy at best. in my experience... look into flashing another if need be.
Total stab in the dark here but, if you have a "task killer app" installed that may be the issue. While it will as intended, the OS will just restart them and "that" kills battery. If that isn't the case, disregard and good luck!