It's a pity we don't get more European sales updates often.
If I combine the 3DS and WiiU's launch period sales together from previous information listed in here and in the Japanese Media Create threads, then compare it to the Switch's first month, it sorta looks like this...
Switch (March 2017)
Japan: 565,013 (First month)
US: 906,000 ( First month)
Total: 1,471,013
3DS (Feb/March 2011 to July 2011)
Japan: 1,306,156 (First 5 months)
US: 922,000 (First 5 months)
Total: 2,228,156
Wii U (Nov/Dec 2012 to May 2013)
Japan: 909,247 (First 5 months)
USL: 1,079,000 ( First 5 months)
Total: 1,988,247
Given the Switch stock issues faced in the US/Japan, plus all the news of the Switch selling great in Spain, France and so-so in other European countries (Correct me if I'm wrong here), I think it safe to say it's in a much better position than the previous two Nintendo devices.
Good for Nintendo!