Lemon vs lime in choc chip cookie recipe
It's really hard to say without seeing your recipe. (Why is there lemon juice in the first place?) In general, lime juice will provide about the same amount of acidity (good), and the flavor will be similar but not quite the same (probably okay, maybe won't go as well with the chocolate). If you've made this before and you can't really taste the lemon juice flavor in the final product, then don't worry about it. If you haven't, well, I doubt half a teaspoon in a whole batch of cookies is providing substantial flavor, so I'd say go for it, unless the cookies are for something really important.