I too had the nightly restarts. Here is what I did and my positive results:
1) I used Silent Boot to quiet the restarts during the night. Note that this application does not work with fast Boot enabled (under settings, applications).
2) I cleared the cache directory as documented for the second GB update:
a) Boot into recovery
b) Press and hold Power, Choose "Restart" option
c) When screen turns off, press and hold Volume Down and Power
d) When the white HBOOT screen appears, use the volume button to move down to ?RECOVERY.?
e) Press the Power button to select ?RECOVERY.?
f) When the triangle and exclamation appears, hold the Volume Up and Power button at the same time.
g) Using the volume button, scroll down to ?Wipe cache partition? and select it.
h) Select "Reboot system now"
3) I freed memory. Even though you have a lot internal storage, you need both ?phone memory? and ?data storage.? This is the same method that I used to get the GB update/patch to install in the late fall.
a) Phone memory ? I freed 375 MB
4) Data Storage ? I freed 50 MB ? My advice is to delete the data under Contact Storage, My contact storage had ballooned to 23 MB. It refreshed from my Google Contacts at just over 1 MB.
5) I used Bootlog Uptime to document that my phone is no longer restarting each night.
Once I cleared the cache directory and freed memory, I was done with the nightly reboots. I have been clear for two nights. I hope that I am not speaking too soon.