Do nuts go rancid after the expiration date? If not right away, how long after?

Rancidity is not switch that is either on or off. Imagine a line that runs between "fresh" and "oh my god what is that smell?" Your nose knows for sure at some point, but it can't detect the buildup of free radicals that happens continously from the time the nuts are picked. Free radicals = bad.

Storage conditions have everything to do with shelf life. If the nuts were stored in an air-tight container and / or under some degree of refrigeration, they may still be "good".

One clue is to break a few into pieces. If they're soft, if they don't snap, they're probably past due for disposal.

Once I've opened a container of nuts, I store it in the refrigerator. Give them a smell. If it sends you reeling, they're rancid. You'll never forget that smell.

Don't wait for them to go rancid, just put them in the freezer.

Taste them if they taste ok go for it. But the will go rancid at some point.