I'm not assuming anything, I'm going by the SPCR table here
That's a little incomplusive I'm afraid. At the low power levels (what you'll be using) The Nexus is shown as 11dB although I'm guessing this is around the noise floor of the chamber. The G360 is simply shown as <13dB. Whether or not this is the noise floor or not I'm not sure but I wouldn't draw conclusions from this. The Value 430 doesn't figure there and really can't be recommended with it's age - it has been retired from the SPCR editors choice list IIRC.
Nexus have a revamped version (v1) of the NX-5000 but according to their own graphs idle load noise is higher than the old version :/
There are advantages to it in that it is much more efficient so the noise level is not everything and can be modded with a slower fan to match the older model. What is perhaps dissappointing is that they reference the SPCR Editor's choice award but that was given to the previous version which has nothing to do with the latest version! It could even be made by a different company. This is bad on Nexus' behalf.
I still wouldn't buy the updated Nexus as it's only 80% Silver, isn't that cheap for it's spec and you don't need anything like that level of power. Either save a big chunk of money and go for something cheaper like the G series or stump up the cash for a fanless Kingwin, Superflower or Seasonic.