Was my pre-packaged buffalo style chicken slices safe to eat?

So sorry to hear about this, Jennifer—never a fun realization! Hope you wound up feeling fine. Our advice is to always abide by expiration dates, though we know things can pile up or wind up forgotten in the fridge. Something that's worked for our staff is having a dedicated clean-out-the-fridge day each week, checking those best-by dates and using up anything before it's too late.