This is a very Western-centric way of thinking. The Japanese are culturally oriented toward "saving face" rather than directly confronting things like this. It's very likely that Nintendo approached their own government with private complaints, and the government is handling it diplomatically, rather than Nintendo causing more drama for their company (and country) by immediately suing the US government.
Nintendo specifically is known to sue first, ask questions later. They just like to shake down the little guys, like their own fans.
Nintendo's model relies on the target not fighting back. Suing the US government is unwise for that reason.
That's a very Orientalistic interpretation of what we have, where a Japanese company is understandably afraid of a batshit crazy leader of the world's most powerful nation with a history of exceptionalism and ignoring international laws, so like any other good capitalist organization, they want to solve it through a "gentlemen's agreement" rather than attacking the emperor and risk hurting shareholder values.
And this is its own stereotyped vision coming from, well i don't even know what you're allowed to call it these days but i guess it controls the progressive left now?