To launch a clean Chrome using JavaScript,
function LaunchChrome()
{
var URL = "https://www.w3schools.com/html/default.asp";
Browsers.Item("chrome").RunOptions = "--user-data-dir=C:\\Temp\\User1";
Browsers.Item("chrome").Run(URL);
}
Note, this will create a new profile called User1, and you need to install SmartBear Test Extension within this user profile.
You can also try with the following options,
--aggressive-cache-discard
--disable-cache
--disable-application-cache
--incognito
But you still need to install the SmartBear Test Extension, for TestComplete to actually work!
This is a functionality of the Chromium browser.