The wife's Nook Color was doing something similar and it turned out to be the cord and not the charger. I discovered this by putting my cord with her charger. If you're under warranty, the charger and cord are covered, you just have to get someone to actually send one.
Forget about chat, I was promised one would be sent 3 different times and unless it's coming on a slow boat from India, it was never sent. I also called a couple of times and emailed a few times. Supposedly one is one the way now.
Last night before I went to sleep I noticed some odd behavior with my charger. It showed 100% charged, but instead of the light staying steadily green, it alternated between orange, yellow and green.
I then left the nook unplugged. It was at 59% after some texting, but after trying to charge it back up today, it is stuck at 59%. It simply says "Not charging" However, the 59% battery usage hasn't not moved up or down at all, which is weird, if the charger truly isn't working.
What should I do next to see about getting a new charger (or whatever else I need) ?
Were you able to receive a new charger? if not...
The charger is covered by the manufacturer's standard one year warranty. If it is within the year you should be able to receive a charger no questions asked. You can call 1800-THE-BOOK, contact chat support, or stop by at your local store. The store can order you a charger, all they need is your email address or your device serial number. Good luck and let us know how you make out.