All polishes have there use. Sadly they all advertise "works on all metals".
Not true.
Nev-R-Dull works ok for the brass rails in my bar. It will scratch soft metal. Not a very user friendly product. Won't buy any more.
WD-40 does not evaporate completely and leaves a residue that dirt/dust clings to. Not a fan.
Flitz works well but at $10 bucks a tube spendy. Picked up some Mr. Metal polish for like 4 bucks. It has ammonia content which is not good for nickle plate. Great on chrome. Use it first and then follow with Flitz and a buff and all is well.
Nickle plate my go-to is Mothers Mag Polish Aluminum wheel polish.
Micro fibre towels for all wiping/drying along the way. They don't scratch and are are cheap at the dollar store.
Soaking parts for 24 hrs. in a 90/10 Water/Blue Dawn dish washing soap solution will get most off the outer layers of crud off. Easier to polish after such.
If able, toss parts in a vibrating tumbler. Hand/Buffer polish one more time and parts should be as shiny as they will get.
That's all I know on the subject. Any questions just ask. Good luck on your project!!
Creighton