Lawsuit to what? Their CAD files, the build instructions? The board shipped with the Nintendo Wii?
Using a brand name like this just makes things easier when Nintendo attorneys barely have to roll out of bed when sending a cease and desist order.
Just call it Kawaii and stay slightly under the radar. Sadly, Nintendo will probably come for you anyways.
Still not in prison.
Needless to say, they are pretty safe from Nintendo. If these guys aren't selling the schematics, and posting them for free, Nintendo has a lot less of a leg to stand on.
And they will use the logo as a way in.
https://retrocomputing.stackexchange.com/questions/11736/why...
Consistent inaction against infringers can lead to the public perceiving the trademark as less distinctive. This can make it harder to protect the trademark in the future, and can encouraging further infringement.
That's commerce.
Now, obviously: Their target market knows exactly what they're buying, and they aren't going to be confused by any of this at all.
But trademark law (and the surrounding case law) may not see it that way.
It's easier (and a lot less fear-inducing) to cease-and-desist before Nintendo's IP lawyers send a nastygram than it is to do so afterward. (And in order to keep their trademark intact, they pretty much have to send that nastygram. Trademarks are very much a defend-it-or-lose-it thing.)
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"Sorry guys, the first order had to be scrapped along with all of the money we collected and spent on it. If anyone is still interested, the price is still $55 for a shell without the logo if we can get another 30 orders in again."