DR Danise - Soaking chestnuts in salt water doesn't really "salt" them. The salt in the soaking water helps to draw out any extra moisture in the chestnuts. Any "saltiness" is just a result of any soaking water left in the chestnut. Since you're diluting the salt in water, you would have to add a copious amount of salt in order to make a difference. However...
If you start off the soak in warm(!) salted water, that will help a little. Or you could soak them in salted water, then bring them up to boil in the salted water for a minute or two. Then take them out of the water and put them in the oven to roast.
Or just REALLY salt the water. -Of course, as for salt and sodium... Didn't you see the article I posted earlier?

*Personally, I like my chestnuts on the sweet side.