As much as I love chocolate chips in cookies, would the recipe still work as well with sultanas?
Items that are mixed in to a cookie dough at the end of a recipe (such as chocolate chips, nuts, sultanas/golden raisins, peanut butter chips or regular raisins) generally don't affect the structure of the dough and are often interchangeable, as long as you keep to about the same total weight of mix-ins as in the recipe. The main consideration is how well the mix-ins will match the actual cookie itself.
If the cookie is supposed to be eaten just warm, with slightly squidgy chocolate chunks inside then a raisin may be slightly disappointing in comparison. If you are not sure then you could always use half chocolate and half sultanas in the cookies and see which you prefer. Otherwise you can pretty much use the mix-ins you prefer - or go for a "fully loaded" cookie with a combination of different mix-ins.