[Chasing]

Brand shouldn't matter, from my experience. I use SO much clear nail polish because of SO-DO figures. None of it has directly damaged my plastic as long as I applied it properly. I HIGHLY recommend getting the rapid-drying ones, which are a dollar at your convenience store. I'd say it's absolutely required - you don't want the nail polish to drip before it actually solidifies.

The big thing you need to keep in mind is to NEVER brush the nail polish on - you drip it. Pretend they're eye drops(don't actually put them in your eyes though lol). The reason for this is that brushing/swiping nail polish onto the surface of a sticker will absolutely ruin it. If you mess up, DOUBLE DOWN, apply more nail polish - just make sure you never brush. Once you've got it down, it won't even feel like a sticker anymore, which is so awesome.

I've used 4 different brands of clear nail polish and none of them have directly damaged anything I collect, which includes RKF, SHF, Gunpla, and SO-DO.