In my case using a Raspberry Pi Zero W with Hassio image 2.10, my wifi access point or SSID was not showing up in the list created by nmcli device wifi
.
A few google searches later, I found a raspberry pi forum post hinting that the SSID that you’re trying to connect to with your Hassio install and CONFIG USB method, must have a channel<=10 on your Router.
I reflashed my SD card, plugged in the CONFIG USB, booted up and waited around 2 min and was then able to connect to hassio.local:8123
. This finally solved my wifi connection setup problem!