The Switch dock requires the 15V PD profile, which the (old) 61W adapter from 2016 did not support, but the newer 61W adapter from 2018 does.

A USB-C PD brink specifies which voltage and amp combos it supports charging, and the one that the dock & switch ask for as their 'optimal' power profiles most apple USB-C bricks do not deliver, despite having the wattage capability for them.