What would you use?

Brass is brass.

Nickle Winchester brass is what we shot in the Army AMU in Model 52's.

When reloaded, the nickle will tend to flake off after a few sizings.

It will not harm carbide dies or guns.

If ya got'em, load'em.

rc

Mainly, just treat it like any other brass. In some calibers it can be a little harder to re-size, but in 38 spl you shouldn't notice a difference. (At least I don't).

The nickle plating is harder than regular brass, so clean them before sizing to avoid scratching dies, especially if you use plain steel dies. You should clean all your brass anyway, whether by simply wiping it off or by tumbling.

About the only real difference I've seen over the years is that nickle plated brass seems to split before plain brass will. Shoot them until the the necks split, then toss them, just like with regular brass.

As mentioned, nickel cases are more prone to cracking and splitting.
Also, I don't like seeing specs of nickel that have flaked-off in the action of my auto loaders.
I collect a lot of brass at the range but I invariably throw the nickel cases in the garbage during sorting.
That may not be to everyone's liking but that's the way I roll.