If your intent was to increase the Calcium Hardness (CH) in your pool, then no, you cannot use potassium chloride for that purpose. It is the "calcium" in calcium chloride that increases CH; potassium won't do that.
If your intent was to deice, then yes, potassium chloride can be used but recognize that it is similar to regular salt (sodium chloride) except it is not as harsh on plants, but note that like regular salt, it will not work well at lower temperatures below around 15F. Calcium chloride works well even at very low temperatures.