Ubisoft recently published their Q2 2018-19 sales results. In their report, they did a breakdown of revenue based on the various platforms available. According to their data, 3% of their Q2 2018-19 revenue came from the Nintendo Switch. Just Dance 2019 and Starlink: Battle For Atlas were not available at the time, so their sales are not included in this data. A tweet relayed the news, so you can see the full revenue breakdown for yourself down below.
Source: N4G PC 3% Of Ubisofts Total Sales In The Second Quarter Of 2018-19 Came From The Nintendo Switch