NSS diagnostic question

Yup, pull the NSS wire off the starter relay and replace it with a jumper wire from the terminal to ground. If the car now starts, it's going to be the wiring down to the NSS, the switch itself, or, an internal transmission problem. If the car still doesn't start with the key, check to make sure you're getting 12V juice to the starter relay wire from the ignition switch in the start position. As mentioned, make sure the transmission is in Park/neutral and the E-brake is fully engaged, or rear wheels off the ground when doing these tests.