Google does not provide a standard file for ChromeOS. Instead, the modern, official way to install it on PCs and Macs is via ChromeOS Flex , which uses a image file.
If you truly want a classic ISO file, you should look at – the open-source project that Google uses as the foundation for Chrome OS. Unlike Chrome OS, Chromium OS can be compiled into a bootable ISO. chrome os iso file 64 bit download