Nicecast has been superseded by Audio Hijack. While Nicecast may still work on older versions of macOS, it's no longer supported by the developer. Instead, use Audio Hijack.
Download Nicecast. Nicecast includes a 60 minute trial period per app launch. You can purchase a license for longer broadcasts at the link above.
Press CMD+2 on your keyboard to show the Server Window.
There will be a 'drawer' on either the left or right of the window called 'Server'.
Click the '+' button at the bottom to add a new server to the list.
Give your server a pet name, In this example, we are using 'Radio.co' then choose 'Shoutcast' as the server type.
Complete the select field below with the information presented in the Live panel on your Radio.co dashboard. For example:
Choosing a Source
The last stage before you start streaming is choosing your connection source. For example, you could select an application, like iTunes. Your radio station will then broadcast whatever is playing through iTunes. Alternatively, you may want to use more than one application and a microphone so you could select the system audio. This will then broadcast whatever is playing through your Mac Sound-Card or connected USB interface.
Note: If playing tracks using Apple Music, Nicecast will NOT broadcast the track metadata due to copyright reasons.
Once you are ready to go, click 'Start Broadcast'. The software will connect to Radio.co and you will be able to see the status in the Live DJ bar at the top of the Radio.co Dashboard.
NOTE: You can only go live when the live event starts. If you try to connect to the system before the start time, your broadcast software will show an error.