You can probably get by with just a new seal and a new nut, but I would question getting a new crush washer also.
I have seen many crush washers that won't crush, so people reuse or the pre-crush the washer in a vise, therefore it should not be used. So your call on that. I would check to see if the bearings are good by trying to move the pinion up and down or side to side. There has to be a reason there is a leak.
How many miles?