The way that tariffs work is, some specific person (often a corporate person) performs the act of importation into the United States, and that person is charged an amount which they need to pay before they're allowed to take their goods from the warehouse. In this case Nintendo is that person, and both they and the government presumably have records of what they paid.

Whether some downstream consumer of those imported goods paid a price that would have been lower if not for the tariff is a commercial question between them and whoever they paid. Maybe they would have, maybe they wouldn't have. There isn't any objective way to calculate what the price of suchandsuch Nintendo product would have been in the counterfactual.