What confuses me about this setup is the NS2. In my setup (5150-II, by the way), I have an ICP decimator prorackG which has 2 channels, I think this is the source of my confusion here, because the Boss pedal my be different?.
In my case, the chain is:
Guitar - decimator channel1 - amp
Effects send (amp) - decimator channel2 - Effects return (amp)
Coupled with this, the way you've drawn the diagram has the following route:
Guitar - NS2 - Delay - Effects return
Is this an error on your diagram?
If the Boss is NOT a 2-channel noise reduction system (I don't believe it is?), then I guess it acts as a parallel switcher, and can be put in the effects loop as discussed above (ie not before the main input of the amp). If it is a 2-channel system like the Decimator, it just complicates things a bit! :)
Roo