If the slot in the crankshaft for the key is okay, then yes you can install a new key, put the pulley back on and torque the bolt. The key has to fit real tight, any play at all and you'll probably be dead in the water again. If it all works out, you might want to put medium strength lock tite on the bolt.
Although I don't drive a Nissan, I do work on them.
DD is a 2005 Honda Accord and my Work horse is a 1994 Ford F350,CC,LB,DRW with a 7.3 IDI diesel engine.
Last edited by chuckster57; Nov 22nd, 2012 at 01:25 PM.