2018 Nissan Titan brake won't in gauge so I can't start vehicle

This is a frequent problem on Nissans. The brake switch can fail, on top of the brake pedal, under the dash there is a switch assembly. Rock the connectors back and forth and lighty tap on the unit, while pushing the pedal in and releasing it. Try to start it. If it doesn't work keep trying. A 2018 will be under warranty, if you can get it going using this method, take it straight to the dealer. There will come a point that the jiggle trick no longer works (probably the next day), and you will be completely stranded.

It is under warranty so call the dealership's service department for instructions. My guess is that they will have it towed (free of charge) to their shop for repairs.

On the Titans there is a by pass to allow the gear shift lever to operate, even without a key FOB; there is a little red button on the right side of the steering column, just under the shift lever, it’s behind a square cap on the plastic steering wheel cover, pop the square cover cap off and the rod button is exposed, just push it in with your pinky finger and the shift lever can be operated ...