Does nutritional yeast go bad?

Just to reiterate ChefOno, ignore the answers that are for baking yeast. And don't mix the 2 up!

Um, nutritional yeast isn't the same thing as yeast for baking. It's dead at the time of purchase.

But, yes, all foods are subject to degradation; temperature, light and moisture being factors in how long such changes take to occur.

I make bake a lot of bread and buy yeast in a large quantity because of economics. I keep about a months worth in a tightly sealed jar, and
The rest in in freezer. I have kept frozen yeast
for a very long time with no deterioration.

You can keep it up to a year, in an airtight container stored in a dark place like a cupboard. Hope this helps! It's best if you buy quantities you can use in less time, so that it's at its freshest.

It is my experience that all yeast "goes bad". It's got a shelf life ... even the dried stuff is no good after time.