To find out the nutritional value of most anything type into Google the ingredient you want and then nutritional value. Most things should come up.
But, do you really mean the sodium content? No potassium level is listed for hoisin that I can see. However, the sodium content is 260 mg. per TBS and there are 3 tsp. to a tablespoon making it 86.67 mg. of sodium per tsp. of hoisin.