I've played it before. There were plans to make a NES or SNES version of CoTAB but that didn't happen. But if you want, (not to spoil it) at the end of the PoR NES you can get character sheet codes that would have allowed you to transfer your character to the CoTAB nintendo version.
I like the fact there was no encumbrance restrictions in the NES version however you can only have a 5 member party. plus you were limited to what races/classes the selection screen gave you.
Some of the spells were renamed like bless and prayer. Plus no gambling allowed in the taverns.
the music is annoying but you can turn it off. but the green brown blue colours are a bit well blah..
. and being 8bit the graphics are not at all like the ones in the other versions of PoR
Plus the resting aspect took tooooo long to heal your characters. seemed like forever from what I remember when I played it.
But I think if you can find the NES cart (box instructions etc) it would be a great addition for the D&D collector. I'm also guessing you would have to replace the coin battery in the game cart by now (being over 20 years old).