Others have used maple syrup for fermentables and report it adds a nice smoky flavor to the beer. Thanks for reminding me, I meant to try that someday.
Maple syrup has some fermentable sugars in it, so you'll want to compensate with less corn sugar if you want to add the syrup. I don't know what ratio to use. You'll probably have to dilute it a bit and use a hydrometer to estimate how much of it to add. It would probably be a lot safer to add the maple syrup into the boil and let it ferment with the rest of the beer, and stick with corn sugar for bottling.