The sweet spot here is sticking to two parts dry sparkling wine to one part orange juice. Always start by getting that chilled juice into the glass first, then ease the bubbly in gently; the simple action of pouring will blend everything naturally without knocking out all the lively bubbles.
A crisp, dry Prosecco or Cava balances the natural sweetness of the juice like a charm. Make sure both bottles are properly cold and hold off on mixing until right when you are ready to drink. If you are hosting a crowd, stir the exact same ratio together in a pitcher at the very last second so nobody gets stuck with a flat glass.