Not Andy-
Nickel is more yellow in color than chrome.
Luster is a function of polish (level) - you can dull things by scratching it with abrasive but people who do it with care, make sure to make sure they have the pattern go the depth and direction they want.
Rarely, do I ever finish the blade to high luster (unless it has a hamon), finishing at no more than 800 grit on the primary bevel (blade).
I’d use some kind of motorized wheel or belt, but those things can yank parts out of your hand occasionally.