While my case is a Cooler Master, not an NZXT, here's what I did. Maybe it will give you some ideas:
In this first photo you see the entire bundle of wires leaving my PC Power & Cooling 750W PSU. PC P&C gives you more wire than you could possibly ever need. The entire bundle is routed into the uppermost 5 1/2" drive bay where I cut metal to connect two slots on the motherboard tray side of the drive bay. Then the entire bundle of wires is unbundled and each of the wires is fed through the expanded slot. All of the excess wire and connectors are then spread out and stored between the motherboard tray and the non-opening side panal of the case.

In this photo you can see the flopy disc wire and power connectors exiting from behind the top of the 3 1/2" drive bays. Thte SATA cables also went through a hole to get behind the motherboard tray. Some of them also exit from this same area and go up to the optical drives. More SATA cables exit lower along the drive bays to connect the hard drives. About the only wire "mess" is the power connections to the hard drives as there are several connectors on a single cable.

I wanted to do as little cutting as possible when I did this so thankfully there were some well placed holes in the case frame as it was. I did have to drill one other hole so I could get the rear fan cable behind the motherboard tray. It exits at the bottom center of the case, as do a few other lower wires, and plugs into a 4 pin connector at the bottom of the mobo.
And here's the final job. Not entirely wire free but pretty clean.

And yes, mine looked a lot like the pics Dragon posted as I was doing this. Dragon is also correct in telling you it's a complete disassemble and start over.