ALL holsters will wear ALL finishes.
The only way to prevent finish wear is to never use or holster the gun.
How much the holster wears a nickel finish depends on the holster, how you use it, and other factors.
Leather will wear the finish over a wider and wider area as the holster stretches and flexes.
Kydex will quickly wear finishes, but in only certain areas where the holster makes contact with the gun.
Since good Kydex holsters only make contact in some areas, wear is limited to only those areas.
A suede or pigskin lined holster will often wear the finish WORSE.
Dirt and grit gets trapped in the soft leather and turns the inside into what amounts to a sandpaper lined bag.
The least damaging holsters are a modern HARD leather holster that you replace as soon as the leather starts to stretch and wear and allows the gun to start shifting in the holster, and a good grade Kydex holster, which will last a LONG time.