where can I find a passenger side front wiring harness and how much does it cost

Hello, you can try your local quality automotive parts store. You could try your Nissan dealership. Both may not have any luck -- this part may or may not be available without the entire harness. A used parts supplier like LKQ may be a good option to check out as well. My suggestion would be to interface with someone locally -- like a Nissan dealership or Nissan specialized technician - to see if they have any good leads or sources.