With NWBC it is pretty straightforward to create a desktop shortcut which directly opens NWBC with a defined system/client. The shortcuts look like this on your desktop:
In them you basically you need to define the following components:
In total the link looks then like this:
sap-nwbc://https://tmsystem1.tm.corp:12345/sap/bc/nwbc?sap-client=700
Double clicking on it directly opens the URL.
Some more information can be found here.