Without trying to start the engine, just turn the ignition key to the "ON" position so that the dash lights come on. Put the car in Reverse (Engine NOT running!) and go back and see if the clear backup lights come on.
If they aren't on, you have either a mis-adjusted - or bad - NSS on the trans, or both light bulbs could be brunt out.
Do you have the manual that tells you how to set up the NSS?