I own the NHT SB-3's and a C372 and have found that they match up very well. NHT's like a lot of power, so in general, the more the better. Compared to many other speakers you will find that you have to bump up the volume knob up a bit with NHT.
That said, NAD integrated amps are so conservatively rated in power specs that depending on your room size and preferred listening levels it is conceivable that any of the three NAD's mentioned might suffice. If you have a larger room and like to listen loud, go for more power. Smaller rooms and lower listening levels will require less.
One more suggestion. Unless you are committed to getting bookshelf speakers, you might consider the NHT ST-4 floorstanders (that I also own) that sound almost identical to the SB-3's except in the bass, where the ST-4's go much deeper without sounding strained. The ST-4's are really not that much more expensive if you also need to buy some good speaker stands for the SB-3's.