Elgato Game Capture HD60 S+ has a stereo analog line-in port which can be used to capture analog audio like that from Elgato Chat Link. Changing the audio input for the Game Capture HD60 S+ must be configured in Elgato software. For Windows, this would be Elgato 4K Capture Utility. For macOS, this would be Game Capture HD.
Selecting the Analog Line-In as the Audio Input on Windows
1) Open 4K Capture Utility.
2) Go to Settings, then the Device tab.
3) From here go to the Audio Input selection and change it from HDMI Audio to Analog Audio.
4) Click on Apply and then on OK to close the settings.
5) Now you can close the 4K Capture Utility and open the 3rd party software such as OBS Studio.
Selecting the Analog Line-In as the Audio Input on MacOS
1) Open Game Capture HD.
2) Go to Device Settings.
3) From here go to the Input selection, and make sure that with Analog Audio is checked.
4) Click on OK to close the settings.
5) Now you can close the Game Capture HD and open the 3rd party software such as OBS Studio.
Audio will now be captured from the analog line-in port on the Elgato Game Capture HD60 S+ and be available in third party software.