That's a tough one to answer, because your'e talking about weight versus volume. By volume, 8oz = 1 cup, but depending on the size of your chocolate chips, that may or may not be accurate.
Using a scale will give you the most accurate measurement, but it really isn't necessary. With most recipes, it's okay to guesstimate the quantity on chocolate chips--they don't strongly influence the chemistry of baking, they just add a little texture and flavor. So using a little more or less than is recommended usually won't hurt.
If it helps, a standard bag of chocolate chips is 12-13oz, depending on the brand--and the exact weight will be listed on the bag itself. So 6 oz = just under half a bag of chocolate chips.