It would be interesting.
1. You may be suing the wrong person. At least in the UK, it's the store you bought the product from that is legally liable to make sure it's fit for purpose.
With the disclaimer on the back of the box that modified systems may render it permanently unplayable.
https://www.reddit.com/r/NintendoSwitchBoxArt/comments/7eukco/la_noire_box_art_without_banner/
If you were banned after buying the game, then it's likely you don't have any recourse against anyone. The game worked when you bought it, there was a warning on the box and your actions stopped it working.
If you were banned before buying the game, then you could argue that you didn't get to read the warning before purchasing and get a refund. But you'd have to show proof that you tried to get a refund from the store and you were denied. In this case you should probably sell the game second hand and sue for the difference, otherwise you haven't done enough to mitigate your losses.
2. By taking part in the class action you would be disclosing a crime,
https://neurogadget.net/2016/06/24/jailbreaking-the-ps4-and-xbox-one-consoles-is-illegal/34026, which nintendo would certainly turn up to seek damages for. Bringing a case against them would save them a whole lot of time and money.
There is a scene release that includes the NSP, so you can just grab that if you need it.
If you bought the game and played it before being banned then you're ok as the necessary "update" was downloaded from eshop already.
If you downloaded the scene release of la noire, then that comes with the XCI and NSP, you need to have installed it but I guess you did.
I have a vague feeling that originally the bans nintendo were dishing out still allowed updates, but now they don't. So you may have been able to download it anyway.
Arguably by banning modified systems they are protecting actual consumers online against cheaters.
I agree their track record on people who buy their consoles and then try to pirate the shit out of all the games is poor.
What specifically did you have in mind for their anti-consumer practices?