You might not need an app for voice chat after all.
Switch PDP headset listing description says:
"Experience your favorite games without boundaries and stay connected to friends during exciting adventures with the Afterglow LVL 3 Gaming Stereo Headset for Nintendo Switch. Block out distractions with the flexible boom and noise-canceling microphone and adjust volume with the easily accessible in-line controls. Plug in your headset to your system,"
http://www.gamestop.com/accessories/afterglow-lvl-3-stereo-headset-for-nintendo-switch/140248
“Simple minds have always confused great honesty with great rudeness.” - Sherlock Holmes, Elementary (2013).
"Did you guys expected some actual rational fact-based reasoning? ...you should already know I'm all about BS and fraudulence." - FunFan, VGchartz (2016)