Place chocolate in a heatproof bowl set over a pot of simmering water (do not let the bowl touch the water). Cook, stirring frequently, until melted.
Add the popcorn to an extra-large bowl (or divide between 2 large bowls) and spoon the melted white chocolate over it in batches, tossing to coat after each addition. Sprinkle with 2 tablespoons of the sprinkles and a pinch of salt, tossing to incorporate.