Nail polish remover is Acetone, which is a pretty viscious solvent and will disssolve a lot of inks and some plastics. It is also highly volatile.
Meths is much less viscious and takes off permanent markers with no problem.
I prefer to use a permanent marker on my chart (though I don't use it on the computer). I carry a very small amount of meths in a tiny plastic shampoo bottle (the type you get in hotel bathrooms that holds about a dessertspoon) and a small scrap of cloth. You only need a tiny amount so it lasts forever.
Mike