I presumed it meant something along the lines of 'No Disclosure Agreement'. I guessed by the context. Basically he can't tell anyone about the project.
Despite what I said about the goldmine, I also have my doubts about a new Banjo platformer, to be honest. I actually find myself liking Yooka-Laylee more; Banjo's abilities are admitedly quite sluggish nowadays, just as parodied in Nuts & Bolts. Even with talon trot, Yooka and Laylee just seem so much more fluid to me -- not to mention fresh and exciting.
However, Banjo was a huge part of my childhood, so I will stand by that Rare need to make Banjo 3. Preferably following on from Tooie story-wise... and hopefully re-exploring old levels back in the lair/Isle O' Hags, as well as brand new areas connected to them.
I actually think the most sensible thing to do would be a rehaul of the whole series to introduce it to kids. Maybe a HD remake of Banjo-Kazooie with significant additions and changes to make it fresh, but extremely nostalgic. Hmm...
(I'm not really thinking this through, just rambling).