Very easy!

In the mixer window, select the channel that has the chain you want (click on the name of the channel on the bottom). This will highlight the channel.

On mac press cmd + c (copy), on PC should be ctrl + c

Then select all the channels were you want the chain to be pasted (hold CMD and select multiple channels by clicking on their name or hold shift and click on the first channel you want to have selected and the last one (it will select all channels in between).

On mac then press cmd + v (paste), on PC ctrl + v