I'm sad to report that there is no MHL (video out) from the Nook HD+ using a female USB adapter and USB to MHL HDMI adapter. This usually works great with most tablets and phones. I even used a 5 pin to 11 pin adapter (USB pinnage setup that newer Galaxy products use Galaxy 3, 4 Note 2, 3, 8, etc.) but no luck.
The capability is there since B&N have an HDMI adapter, so I guess it needs a hack on the ROM like the one verygreen did to enable USB OTG (USB host) on CM.
There is a coupon for 20% off on accesories that ttablet posted and it works since I personally checked online against the purchase of the HDMI Adapter. The coupon is good until Octorber 14, 2013:
20% Discount on Nook Accessories
B&N is having a "Friends & Family" promotion, good for 20% on a single item, through October 14th. Nooks themselves (and Nook content) are excluded, but it appears that Nook accessories that are not already discounted are part of the promo.
The email I got from B&N also says "share this coupon with everyone you know". Promo code is FRIENDNFAM, enter it at checkout at BN.com; it appears that you can also print a coupon that could be used in a store.