I don't think Casa applies here. A nationwide injunction is not the same thing as a universal injunction. A universal injunction benefits non-parties to a case. But if an injunction, especially a TRO, requires nationwide effect to protect the interests of NY, who is a party, then that's fine. Also note that Kalshi is based in NYC, AFAIU; it's not a situation of a state court trying to control the out-of-state actions of a foreign company merely doing business in NY.