Only girls use bearing pullers!!

Pull out the split-pin, Loosen the nut.
Get two kick-ass sized hammers and bash it at the same time either side of the solid part of the joint (not the balljoint itself).
It works everytime. Sometimes it takes a couple of whacks.

The steering boxes are expensive items to get from Nissan. The gear and worm-block wear out after 20 years of normal use. I got one out of a B120 (Ute) from the wreckers, the car had a big front end accident and the steering column and shaft was bent, but the gears were like new! I straightened the shaft and put it in another tube. All good. Sometimes packing shims can help with the mesh, outside using the adjuster screw. But generally the gear wears out in the central area, making for the symptoms you have explained.

I have the Nissan Service Book for the 1200 and I rebuilt my steering box to factory specs.

Chris.