First matter: in Android 4.x, /mnt/sdcard turns out to be connected to the internal memory. The swappable slot appears as /mnt/ext_sdcard. That means that applications written for older Android specifications that may try to store things on the external memory end up using internal memory on HD.
Second: The only B&N content that can be directed to the external memory are videos if you have turned on that option in the settings. Beyond that, you have to sideload stuff (images, third party ebooks) or run an application that can create data on the external memory (Office Suite packages -- spreadsheets and word processing documents that are expected to be shared with a computer).
Third: there are lots of hidden apps. Open the app page, hold down volume up and at the same time hold your finger to the word Apps at the top of the page -- that should activate the hidden app page. Also, if you have multiple profiles on the device, make sure your profile has all content active.
Lastly, after doing deletes you may have to do a full power down and reboot to have the file system recover space.
I have a Nook HD+, is there a way I can store google apps on an SD and run them on my Nook HD+? What's the point of being able to store google apps on sd card if you can't run them on your nook? Also, are they ever going to make a Nook Study app for students like me who buy etextbooks, it would be nice to be able to read them fro my Nook, rather than just my pc. Or have they abandoned the Nook Study altogether without telling anyone?
NookStudy has been abandoned. They now have Yuzu, which appears to be web based.