I'm familiar with that amp - it's a good match for speakers that are a difficult load (like Maggies) and it's a good match for speakers that are not super high resolution like anything from Dynaudio, Wilson, Sonus Faber, etc... ie, pretty much anything that uses scandinavian drivers like Scan Speak. It matches well with those drivers because they are imparting a softness to the sound that's part of their basic design.
But the NX-Otticas are very high resolution and any glare in your partnering amp will show up now. Because they are such an easy load, you don't need a big bruiser of an amp to drive them, you can focus on something with lower watts but higher quality. Things like the Pass X30 or the First Watt Aleph or BA3 (but not, not, not the F5!).
Of course tubes will get you there easier and cheaper. I understand not wanting to mess with them but if you do, I'll 2nd the rec Danny made for the Elekit Japan 300b, it was a great match and is current production. If you feel like 8 watts is not enough, my 2nd rec would be the VTA ST70 with octal driver board (6SN7 tubes) from tubes4hifi.com - they are made in america by people similar to Danny, IMO. They make very high performance amps for very little money (relatively). The amps don't look sexy but they produce just about the best 35 watts per channel around.