You probably used an old version of CWM to flash the CM11 zip. It requires v6045 or newer. And wiping data does not return it to stock. You must flash the stock ROM. Go to my HD/HD+ CWM thread linked in my signature and get the stock ROM zip from item 6.
Sent from my BN NookHD+ using XDA Premium HD app
See my Nook Color Tips Thread here
and my Nook Color EMMC Partition Repair Thread here
and my Nook Color Updated CM SD Installation Instructions here
and my Nook HD/HD+ stock tips thread here
and my Nook HD/HD+ CWM Root Tools thread here
e.mote's Nook HD/HD+ Dummies Guide for installing CM10.1/CM10.2/CM11 here