Actually, they didn't.
All you need to do is simply go to the Google Play Store. They have 100s of FREE comic book apps to solve your problem. Just launch Google Play (or go there on your PC), and do a search for "cbz readers". Then, all that left if choosing which reader (or readers) you want on your tablet.
Hope this helps.
I appreciate the attempt at helping, but if I had wanted to do that, I would have bought something else. I also have an ipod touch and am quite familiar with many of the comic readers over there. I bought a Nook HD specifically because it was a native CBZ reader.
I don't care if the apps are FREE or not. I bought the Nook for one specific purpose that is now being taken away from me. I shouldn't have to use some sort of work around because B&N decided to change the very function of the product five months after I bought it.
Is your Nook overheating. I just discovered on mine if the brightness is up to high it overheats. Try turning down the brightness to a little more than half way and see if that helps. This may not be your problem but I wanted to suggest it in case it is.