Considering that half of World's sales are on PC, and XBox only makes up a small portion of the total numbers, I will say that between Switch and PC it will sell similar to World. If I had to lean one way or the other, I would say it will sell a little more overall given Switch popularity in Japan (MH's biggest market).
The only thing that could hinder this is that World saw a sales boost when prices were slashed to sub 20 USD less than a year from launch. I, for example, got my PS4 copy for 11 USD new. I am not so sure we will see a price cut of that magnitude for a Switch console exclusive.