The cool thing about the NS 2 is that it has a send and return function. I own a CS 3 and NS 2. I'd put the compression first, then the Gate, then run the Gate's Send to the Distortion In, and the Distortion Out to the Gate's Return. Finally, hook the Gate's out to the Amps input. This will stop your Distortion Unit feeding back when you're not playing, and it's also unlikely that a) You'll need to gate clean tones and b) You'll need to run the Distortion and Compression at the same time, as distortion naturally compresses.
If you're adding time-based modulation like Delay and Chorus or a Volume pedal, run them after the NS 2 Out. I have about 8 stomp boxes in my pedal chain - mostly Boss - and that's how I hook them up.