Whatever impact NSBWii has it probably will be too late to allow them to make up their 26 million units of Wii shipped...
They still have a good shot at coming close to their software target though...
The biggest question this raise is wether Nintendo actually understand what made the success of the Wii and what makes people purchase Wiis...
They were clearly surprised by how successfull the Wii was at release, which is why it took them so long to satisfy demand and now once again they seem to have failed to predict what the Wii sales will be for another year...
So that's 2 out of 3 years where they failed to predict accurately sales and they only did good in 2008 because they had total control on sales due to Wii being out of stock most of the year so they sold whatever amount they produced...
That doesn't mean Nintendo is doomed at all though, they are still doing fairly well and they do a much better on the handheld market at predicting consumer behavior.
But clearly they do not seem to have such a good grasp on what makes consumers purchase consoles...