How large a pecan are we talking about?

The first issue will probably be dealing with the stump grindings if you must go in the exact same space. I got away with a fu fu japanese maple about six feet from a good size ash I had ground out. It is still really terrible feeling soil and I hear the rotting wood robs nitrogen from the soil or something.

Digging out all the wood infested soil leaves you with this hole to fill and it is difficult to get the drainage right and do that without sinking or something.

Good luck.

Pecans tend to have significantly lower levels of juglone than say black walnuts. Regardless, red maples are resistant to the allelopathic effects of juglone. I think just grinding out the stump is fine without having to go through the issues of removing the grindings and bringing in fresh soils, settling, etc.

Ideally, I'd wait at least a few weeks before planting to allow any settling to occur. My actual preference would be to give it the winter before planting. By that time rain and weather would have taken care of most of the soil settling issues and the effect of any nitrogen tie-up minimal. Wood material (like grindings, bark, sawdust) mixed into soil will tie up nitrogen availability but this is easily remedied by the application of a high nitrogen fertilizer like blood or alfalfa meal.

Thank you very much for your advice Tornado and Gardengal. I was in a rush to "fill the hole" but I think I will wait the winter. Thanks again.