The best thing Nvidia can do now is just keep drip feeding the stock into the supply chain slowly. If people see more cards becoming available over an extended period then they are less likely to pay the scalpers inflated prices and wait. Sooner or later the scalpers are going to run out of purchasing power and need to sell something.
They should also be limiting the number of cards going to any address/email too.
The way I see it, if I have 1000 units in stock and expect another 1000 in a month, the best way to sell is gradually release them to the market over the month. If I sell the whole lot in the first 24 hours customers are going to be desperate after not seeing any stock released for the rest of the month that they may pay over the price to scalpers. But if they know more are coming available all the time they are more likely to wait.