Don't think you can find a nickeled sight unless it is a extra done at time gun was plated or a take off. You can buy a carbon steel and send it to a shop that does plating or buy a stainless and us as is or polish to match the gun. Unless you lost the sight keep the old one with it.
i thought about it and the nickel slide had blued sights....it has nickel target sights on it now......i have 5 blued ones.....sorry couldn't help.....