Chocolate is edible for decades if kept in an airtight container. There are bars of chocolate still around from the Boer War (1899 - 1902, South Africa) that are perfectly edible because they were kept in the souvenir Queen Victoria tins.

It may have gone a bit pale and chalky looking if it's got warm, but as long as it hasn't melted, settled out into cocoa butter and other stuff, then reset, it'll be fine. You'll know if it has, the chips will be grainy and greasy.

LTS