basic recipe for cookies from cake mix is 2 eggs and 1/2 cup oil or butter. hh mentioned you could melt the butter, is that ok? because if you melt the butter in a normal cookie recipe, they won't turn out right. they'll be flat and spread out. the butter has to be soft, but I don't know in this case.
I made chocolate cookies with nuts out of chocolate cake mix (or brownie mix? i forgot) and it turned out ok. We ate them while they were warm and they just didn't taste right. But I tried them the next day and they were amazinggggg
tasted so good. Normal cookie recipes taste a lot better, but if you're in a hurry or have extra boxes of cake mix around, then try it out.