I looked under the car and saw the floor board had rusted and huge hole in the floorboard… drivers floorboard is rusted, gone, carpet showing exposed to water, rain etc the cost is outrageous to have fixed, more than the car is worth. I know Nissan isn't doing anything about it, but there must be something I can do...right?

If the seams had been properly welded and sealed, the car would be excellent in appearance. As it is, It looks like it has a major rust problem. I can remove the stain with solvents, but then I am just wiping away all the other protective coatings I had applied. Nissan has denied responsibility for this flaw and will only repair it for an outrageous price.