This could be really easy for you. If you will Google this, you won't
believe how many stainless nails will pop up.

However, you will have to input your brand of nailer, nail type and
length.

In your post, you first ask for nails... then you say brads will work.

If brads will work, most straight brads are already galvanized. You
can buy those at HD.

If you actually want galvanized or stainless nails, go to your local
pneumatic fastener shop and buy them there.

DAGS stainless air nails.

Robert