Basically, you're just looking for a solvent that dissolves the polish but not the underlying substrate. Nail polish is basically an organic polymer, like nitrocellulose, dissolved in a volatile solvent, such as ethyl acetate. When the underlying substrate is a polymer, finding a suitable solvent that dissolves the polish polymer without dissolving the substrate polymer can be challenging. Acetone is a very aggressive solvent, which makes it a poor choice because it will dissolve both polymers rapidly. Alcohols are not as good at dissolving polymers in the polish, but neither are they good at dissolving the substrate. Therefore it takes a bit (lot) more work, but you stand a better chance at removing the surface polymer without significantly damaging the polymer underneath. I would start with isopropanol (rubbing alcohol) and see where that gets you. You may also seek out "acetone free nail polish remover". These removers usually have ethyl acetate in them in place of the acetone. The ethyl acetate is a gentler solvent and so will take longer to dissolve (and damage) the underlying substrate, while still removing the surface nail polish. Based on the solubility chart, ABS has better compatibility with isopropanol than ethyl acetate, so it is the safer choice as far as your ABS substrate is concerned... but it may be very inefficient at removing your polish. It all depends on what kind of polish you have on there.
Hope that helps. I personally would try rubbing alcohol first. If no luck, find a non-acetone remover and carefully try to remove the polish without getting the underlying substrate. You should be prepared to accept some surface damage to the ABS, though - the polish itself contained ethyl acetate or some other solvent that probably damaged the ABS surface when it was applied.