The problem is that on a particular host box HKLM\SOFTWARE\Policies\Google\Chrome /v RestoreOnStartup is set to 0x04 which prevents restoration of previously open windows/tabs and that makes ChromePortable completely useless.
I tend to have like a dozen windows 5-6 tabs each and the very reason for taking the latest ChromePortable was to avoid that policy force fed to that box for the locally installed Chrome.
0x04 is "Open a specific page or set of pages" in On startup settings
0x01 is "Continue where you left off" == restore tabs and windows
Since you are already able to virtualize password(s) == intercept registry reads for particular paths can you do the same for HKLM\SOFTWARE\Policies\Google\Chrome /v RestoreOnStartup
The value(s) can be in already present GoogleChromePortable.ini or a new .ini