No, people are just talking about the X1 as it's the most recent Tegra chip. It could be the K1, it could be a custom chip (the N1, perhaps?) or it could even be the upcoming Pascal-based "Parker" SoC.
The reason I was talking about it there is that it would explain why Nvidia would be willing to make a loss on the deal. As a point of reference, AMD
was penalised to the tune of $320 million when they pulled out of a wafer order commitment with Global Foundries a few years back. That's the kind of order of magnitude you'd be looking at if (and it's a bit if) Nvidia had committed to large 20nm purchases from TSMC and they had to renege on them due to poor sales of the Nvidia X1. They'd be desperate to make the sale to Nintendo, as Nintendo would be pretty much the only customer buying in the quantity necessary to cover their wafer commitments, so would be willing to offer Nintendo an absurdly good deal, even to the point of making a loss on each chip sold, as it would still be better than paying the penalty to TSMC.