If you experience connectivity issues with PowerA Switch wireless controllers after applying Nintendo's version 12.0.0 update (distributed April 5, 2021), follow these steps to reconnect your controllers:
- From the HOME Menu, please select "System Settings"
- In the Switch System Settings Menu please select "Controllers and Sensors"
- At the bottom, select the option "Disconnect Controllers"
- Press and hold the SYNC button on the top of the PowerA controller to reconnect your wireless controller(s) as per normal
Nintendo's update article for reference:
Nintendo Support: Nintendo Switch System Updates and Change History