Are nutritional yeast flakes the same thing as the regular yeast I use for baking breads?

No- very different product all together. It’s a delicious flakey almost cheesey flavored product- easy to find at whole foods, or any health food store, or trader joe’s sells it as well. In that recipe i would use more of it, closer to 1/4c and reduce the flour total by 2TB.
Most common brand is by Bragg’s
https://bragg.com/products/bragg-premium-nutritional-yeast-seasoning-salt-free.html

No.