The Nintendo Switch has a 802.11/ac WIFI chip in it, that runs on 2.4ghz AND 5ghz.
So for people who are getting a problem, where you try to hop onto your wireless network and the switch just doesnt see it. But it can see other people's.
This means that most likely your router is using the wrong security settings.
Log in, and locate: "Security" and search for Authentication Method or something using the words TKIP or AES.
The choices are:
3. TKIP+AES (combined together)
You want to select AES and apply settings (possibly reboot) to your router. Then your switch will be able to detect your WIFI again.