Going back a while now, the release of Pokemon Bank in Japan caused a festive Nintendo Network meltdown. The service was sporadic and mostly inaccessible for a few days, with Nintendo and The Pokemon Company eventually resorting to taking Pokemon Bank down.
This year hasn't been anywhere near as dramatic, but there was a brief period of instability on the eShop - likely caused by an influx of Switch systems connecting to the Network and store. It prompted Nintendo to apologise online.
We didn't see any notable issues when checking the eShop for North America or Europe, though we accessed the latter more often. It clearly did affect NA throughout the day; there were some getting by without too many problems while others were a little more unlucky. Some also had a pragmatic and realistic perspective on the issues.
In any case, as we type this the network is running as normal, though previously confirmed maintenance later today / tomorrow may affect some online gaming.
Tuesday, December 26, 2017 8pm Pacific / 11pm Eastern to Wednesday, December 27, 2017 1am Pacific / 4am Eastern
Wednesday, December 27, 2017 4am UK / 5am CET to Wednesday, December 27, 2017 9am UK / 10am CET
Did you have any issues with the Nintendo Network / eShop on Christmas Day?