Olive Tree is excellent, but on the Nook, the Encarta bibles are a bit easier to me. It's a bit easier to move around. Both let you set up Parallel Bibles which is great if I'm having trouble with a translation. Except for the KJV, Encarta isn't free, but it is reasonable.
There are also other free apps out there like YouVersion Bible which for a short time made the NIV available free and has numerous free versions available for download or online.
I came to try that one when my Pastor started to use the NKJV recently.