1997 Nissan Altima Oil leakage

The distributor shaft has an "O" ring seal, mark up the distributor so it goes back in the same position, remove and replace seal, have the seal on hand before removing distributor.

So I don't have to take apart the distributor or anything? Does this call for special tools.

If the leak is external and from the head where the distributor sits no special tools, if it is leaking through the distributor and oil is under the cap, get a new distributor.

Here is a pic of what I am seeing.

It looks like the external distributor "O" ring mark the dist and cyl head so it goes back in the same position, unplug loom and unbolt dist and remove, it's just sits on the outer shaft of the distributor, pick it out and fit a new one, very easy job.