Claiming "multiple patent rights" without mentioning smells like kafkatrapping.

I think that Nintendo's delayed reaction was to gauge how much money it could get from bullying Pocketpair to accept some unfavourable settlement outside the court; if too little the costs would be too high to bother, considering the risk, but now that Palworld sold a bazillion it's more profitable to do so. It might actually backfire if Palworld decides to go through the whole thing, I don't know how Japanese law works in this regard but if Nintendo loses this certainly won't look good for them, and even if they win it might be a pyrrhic victory.