Keep trying, and don't use too much.
Powdered nut. yeast is twice as strong as flaked, so if a recipe calls for flakes (I always assume) and you have powdered, use half the amount.
Not all nut. yeast has B12- check labels. It also has an expiration which is why I buy the refridgerated containers that list content and date. They're Red Star brand.
It can be an acquired taste. I only liked it on popcorn for about the first year, and slowly started incorporating it in sauces. I still don't like too much.
I esp. like it with Braggs amino acids.
I like sauces with raw cashews and nut. yeast best
I don't remember what brewers yeast looks like, but it's nothing like nut. yeast.