pre-ordering for launch is going to be hell
it's going to be a nes classic/amiibo situation for switch launch
2 million units worldwide is nothing
2 million units would definitely fall short for a launch in November. But it's not a November launch.
Nintendo expects to sell through 2 million units in its first 2 weeks on shelf in a slow sales period for the industry.
That also equates to selling 15% of the total sales for Wii U in 2 weeks.
And this is without factoring in how many are shipping immediately after the first 2 weeks.
So no, this is not an amiibo/NES Classic situation. Expect sales to be reminiscent of the PS2's launch in Japan, which was 1.4 million for the first 4 weeks, but dialed further back given a more hesitant buyer.
Also, to put it in perspective, PS4 sold 4.2 million units over the busiest shopping period in North America and Europe. So 2 million units to cover 2 weeks' demand sounds doable.
Not saying you shouldn't pre-order, but unless demand is higher than characteristic for the shopping season we're in by a WIDE margin, I doubt said pre-order won't be filled.