This is a less clearcut answer. Although it is highly unlikely that the switch will be damaged by being plugged into a third-party charger of good quality (thanks to the power delivery regulations of the USB-C protocol), it is not impossible. The most likely "bad" outcome is that the console will charge slowly or not at all. However, it is still best to confirm with a manufacturer, or at least an existing owner of the charging device, that it provides a good charging experience for Switch consoles.