See the Northwestern Gardening forum for a recent thread on bark mulch vs. wood chips. Very informative. Personally, I would go ahead and use the wood chips from the stump as mulch, unless you don't like the rough appearance.

It's perfectly fine to use.

I have heard some horror stories on the soil forum of fungus in wood type mulch. I use also bagged mulch, but I also used bagged mircobark, if I need that. I am sure it will be ok, just a slight note of concern.

I use woodchips in my home garden and at the local park as mulch. I have no problems. In the winter, you might get some fungus growing in your beds, but that is normal for decomposing wood. It hasn't harmed my plants.