Unfortunately, Magnepan is one of companies where you need to spend more money on the amp than you do on the speakers. I wouldn’t recommend the NAD for the 1.7i’s... think about getting something with more current.
I’ve listened to 1.7i’s with Gryphon Diablo 300 and that’s one super powerful amp, and even at that point, it’s not overkill for the Maggie’s...
From what I've heard, the Schiit Audio Tyr mono blocks are supposed to be an excellent choice for the 1.7i's. Relatively affordable as well. No personal experience with them though