You need disable the computer's onboard mic by accessing your sound devices in the hardware section of the control panel. And choose the mic of the headset: Or just check whether the microphone mute switch.
1. Please make sure microphone is not muted.
2.Remove the dirt on the 3.5mm interface
3..Connect the headset directly to the phone for testing if the microphone well.
Yes, E900 Stereo Sound Gaming Headset can work on Nintendo Switch, but you may need set the sound in specific Switch game.
E900 uses the detachable microphone, so you can just unplug if no need of microphone.