The axle looks fine to me. Stand it on it's flange... then grab the hub and see if you can move that vertically. If it's got any movement, break it down and inspect/replace the bearing.
The axle nut is a nyloc and can be reused if you don't bugger it up. If you do or it looks poor... you can get one from A&I for about 40 bucks.
Don't waste your time with foolish pullers when trying to remove the bearing either... pop a few of the studs from the flange so you can get it properly situated in a press and push the shaft out. Just make sure that you support the hub correctly.... and that will take some work. New bearing is heated to ~400 deg and dropped in place.