You can layer an opaque base with a glittery/shimmer top coat, or you can buy polish that just looks like that (Holo Taco for example specialises in holographic polish).

Layer takes longer, as one has to wait for each coat to dry before applying the next, but it’s cheaper than buying a holographic polish outright (Holo tacos polish tends to go for approx $15usd per bottle which is insane, and one would have to pay for shipping as well 😱)