That makes no sense since a triple chain distance is actually shorter when it's on the "granny" gear. The only thing that makes a chain path longer than using it on a road crankset is if the derrailleur has a longer cage to deal with a third crankset ring.

Give it a try. If it's long enough to deal with the big to big combo then it's long enough. If it's too short then box it back up and return it for a chain with more links to use on your touring triple crankset.