Don't know about the Nook, but I have a Kindle (had it for 3 months already) and I use it everywhere.. in a bus, bathroom, waits on a queue... and the charge is good enough that I can take it for a weekend and not worry.
It should definitely last for 4 paperbacks. Maybe your Nook is the color version?
Charge isn't a problem if I plan ahead and charge it before I go. But if I'm packing a few hours before my flight I'll look at my Nook and see that it's gone flat.
It should definitely last for 4 paperbacks. Maybe your Nook is the color version?