Welcome to NICO!
Bet you had a sick feeling in your stomach when you first saw that!
I suspect you'll need to remove the front bumper and possibly the front door on that side, but I'm not sure. There should be a good diagram of everything in the factory service manual - which is available at
http://www.nicoclub.com/FSM/
I would avoid aftermarket replacements from eBay or other sources. I have heard that they're pretty much the same shape, but frequently made of thiner metal, so they're easy to bend while installing them and won't hold up as well. You might luck out and find a used one in the same year and color on
http://www.car-part.com. I did this with my old Hardbody truck, and it matched surprisingly well - of course it was just a truck and it was white, so everything polished up nicely. You can also get OEM new at a discount from
http://www.everythingnissan.com
Good luck!
Heath