On the link above, scroll down to Instrument Assembly...
What you are asking for doesn't really make sense. Cable nut would be part of the cable assembly. Part #4 in the diagram. the only other "nut" near the speedo cable at the fairing is #5 in the diagram, and its to hold the speedo assembly to the fairing.
If you need the actual part number, then type "1" into how many, then click "check out" and it will show you the HD part number.
HD for whole cable assembly, hardware store for just the nut (IMO)