Maybe your EVO isn't giving the Nook enough bandwidth? Or maybe the shop works on a port that the phone hotspot is blocking. Have you tried shop by going to someplace with WIFI and trying there?
Hello Kgirl58. I also have the HTC Evo 4g and I also have the sprint hot spot and have had no problems with any apsect of it. My NC connects well to the hotspot. I'm not sure how you set up the hotspot, but you have to name the SSID and set up the type of security you want, for example mine is set to WPA2 and also select a password of at least 8 ASCII characters.
As far as your NC not connecting to your home router, you are not alone in this. But maybe you just have to tweak a few of your routers settings and you should be ok. You can search these forums for router issues and troubleshooting tips, but it might be best to contact CS of your router and see what they can do to help. This can be a pain too depending on how old your router is and whether or not you can get free CS. So don't give up. You'll love your NC once you get it all straightened out.