You can find NISE VIs in the function pallete in LV if you have installed LabVIEW support when you installed NISE (this is selected by default in the installer if you had LV installed before installing NISE).
Also, choose between niSwitch and NISE based on your need - if all you ever do is connect two channels in your application, then configuring a NISE virtual device is probably an overkill (and so is using a switch in this case:-) . However, if you are going to manage multiple routes, then using NISE configuration will let you create named routes and route groups, which you can then invoke (connect/disconnect) in your application and have the configuration part managed outside your application. The code would then concentrate solely on establishing a necessary connection(s) via connecting a route or a route group, while if you were to use niSwitch for this purpose, you would have to keep the logic of connecting inside your application, together with the list of channels that need to be connected.
Start with using NISE, and see if you like it.
http://www.ni.com/pdf/products/us/3msw112-113.pdf