thundervore has a good point. I looked up the manual for your mobo and got the info I used. But apparently I got the manual for the wrong ASUS board. Today when I hunted several times I got the right manual. Your mobo does have three CHA_FAN headers that operate in true PWM Mode, so they do provide the signal your Hub needs. It also has three OPT_FAN headers that operate similarly, but for those you must configure your own temperature curves. The CHA_FAN headers are pre-programed for your mobo, so you are best to use them and let them do their automatic fan control thing. (See later for a BIOS Setup adjustment you need to make.)
There are basically two types of fan control systems in your machine, both very similar. Each changes the speed of its fans depending on the actual temperature measured in the item to be cooled. The CPU_FAN header manipulates its fan according to a temperature sensor built into the CPU chip, so it is ideal for controlling the actual CPU cooling system. The CHA_FAN headers are based instead on a different temperature sensor built into the mobo by it maker, and so it is ideal for cooling your case.
The NZXT case manual tells you how to use its included fan Hub, and tells you to do what I advised above. That is, to connect it to the only reliable source of PWM signal, the CPU_FAN header, and then to connect all your fans to that Hub. This puts all your fans under control based on the internal CPU chip temperature. But thundervore is correct - it is better to control only the CPU cooling according to that temperature, and to control all your case ventilation fans according to the temperature of the mobo sensor. That can only be done using the Hub IF the mobo CHA_FAN header provides a PWM signal. And your mobo DOES do that, so that's the way to go.
So, first step: disconnect the lead from the Hub to your mobo CPU_FAN header. Disconnect your CPU fan from the Hub, and plug it into the CPU_FAN header. That gets the CPU cooling set up properly.
Now you have two choices. You have a Hub which can control up to eight case fans according to the output of one CHA_FAN header, and it will do that for both 3-pin and 4-pin fans. (One exception below). So you can plug the Hub's lead from the top left corner into one of your mobo's CHA_FAN headers, then plug all your case fans into the Hub's ports. In doing that, you are supposed to plug one of them into the Hub's White Port #1 that has 4 pins. I understand that that port also uses PWM Mode to control its fan, but that method can only work for a 4-pin fan. If you plug a 3-pin fan into that Port #1, it will always run full speed - this is the "exception" I mentioned. But if you have only 3-pin fans and plug them into other ports, the mobo will never get a case fan speed signal, because only Port #1 can report its speed to the mobo. If his happens to you, you may be able to go into BIOS Setup for that CHA_FAN header and tell it to ignore its fan speed so it stops sending you warning messages.
Your other option is to ignore the Hub and simply connect your case fans to mobo CHA_FAN headers. You don't tell us exactly how many case ventilation fans you have, but that might work. HOWEVER, it will not work if all your case fans are pre-installed with THREE-pin type, not 4-pin. Your mobo's CHA_FAN headers all use only the PWM Mode for control, and that cannot control the speed of 3-pin fans. So if your fans are 3-pin, go back to using the Hub, and do NOT connect one of them to the Hub's Port #1.
Finally, look at your manual on p. 3-32, the item "Chassis Fan Q-Fan Control". It indicates that the default setting is "Disabled". If that is true, you must change that to "Enabled" for the particular fan header you are using to connect the Hub, so that the mobo WILL use its automatic control feature for your case fans. After making this change, don't forget to go to the Exit menu and choose to "Save Changes and Reset".
Sorry that my earlier advice was incorrect.