You'll want to keep a couple of things in mind. Firstly salt is not necessary at all. Secondly, boiling a chicken breast will result in dry, chewy chicken. So, I would recommend poaching your chicken breast. That happens in a liquid that is simmering, just below the boil. You will need enough to cover the chicken breast. That liquid can be water, broth...really, any liquid. In terms of the salt, this is where one might "salt to taste". A good tasting poaching liquid probably has enough salt, and should do the trick. Alternately, if using water, add enough salt, maybe a teaspoon at a time, until you like the taste. (Taste before putting the raw chicken in the liquid!) Of course, the chicken breast itself can also be seasoned before and/or after cooking as well. Finally, use a thermometer to check your chicken. When it hits 160 - 165 F it is done.