Why isn't Windows 10 Compatible with CCleaner?
It is
What version of Windows 10 and CCleaner are you using?
As nergal says, it is compatible, I am typing this in Win 10 and have CCleaner installed.
Whoops!...I Shoulda said..Why isn't CCleaner compatible with Chrome?
Again, CCleaner is compatible with Chrome, (and other Chromium based browsers).
What makes you think/say that it isn't?
If you are having a problem then give us the details of what is happening, and we can work out why it's happening and how to put it right.
Just a note re the question that was originally asked, note that older CCleaner versions (below 5.46) are not compatible with the newer versions of Windows 10.