Nintendo just released the app for the Nintendo Switch Online service on iOS and Android.
The apps will allow for voice chat in supported games and provide additional features like SplatNet 2 for Splatoon 2. While the Nintendo Switch is region free, the app is geo restricted to a certain number of countries worldwide so unfortunately the Nintendo Switch is not 100% region free yet. The app will also suspend voice chat if you switch to another app during use. Yes, that is a thing in 2017 when every voice chat solution on mobile works in the background. It also seems locked to portrait mode right now. Read more details about Nintendo Switch online here before it launches as a paid service in 2018. Read our review of Splatoon 2 here.