GoPro Jaws.
I saw others using these:
LynkSpyderLynkSpyder is a rugged chain link fence camera mount. It is designed to allow customers to mount their GoPro and other sports camera to the fence for recording baseball, softball, and other games where chain link and backstop netting is available. LynkSpyder is designed to accommodate nearly any fence situation.
https://lynkspyder.com/