Is nickel plated shot ok to use in an old shotgun?

Recently had an old Stevens 520 passed down to me, and have been thinking of using it for hunting. With it being from the 40's and a fixed full choke slugs and 00 are a no go, and being from cucktario, cant use anything smaller than #1 buck for deer. with the only #1 buck i can find being nickel plated.

I just don't want to fuck up my barrel with it being in pretty decent shape with an immaculate bore.