Read how here:
http://www.barnesandnoble.com/u/Soft...ouch/379003175
Especially the description under "Get version 1.1.2 today." When you do it, notice Step 6:
"6. Your NOOK will automatically recognize the file after a few minutes when it goes to sleep mode, and proceed to install the updates."
In my experience, when you use this update technique, the update does not happen till the Nook goes to sleep. So you might want to shorten the sleep setting on your Nook to get it to go to sleep more quickly, just to shorten the time you have to wait till the update gets done.