Try looking up on the clutch pedal...but it may have been removed....
Push and hold the clutch pedal down then try to crank...
If still no crank, start from the basics...
Make sure trans is in Neutral...and park brake applied
Run a small clip on lead from the Solenoid terminal on the starter and tap the other end of lead to a positive battery source...starter motor should crank, if not, check ground strap battery to engine and engine to chassis.
Get it to crank this way first...then go to next step.
Remove ignition switch from dash, keeping plug attached to the switch...
Turn ignition on and check for 12V battery terminal on switch...
Turn switch to Start,,,check for 12 v on Sol terminal...
If both are ok...run a temporary lead from Sol terminal on switch to Solenoid on Starter...
Turn ign switch to crank and engine should crank...
If yes...you have a wiring loom issue...
In most cases the NSS fails internally....you can bypass it and leave the temp lead in place..
Let us know how you go..