I'm guessing you hold a CASA license as ICAO doesn't issue licenses. The FAA does not convert commercial licenses. You can have your CAA verify your license to the FAA and use it to meet the ATP requirement to hold a commercial with an IR. There are only 8 approved CTP programs for pilots not in a college program or airline employee.
https://www.faa.gov/pilots/training/..._Providers.pdf
You'll also have to pass a TSA background check.