Computer Configuration > Administrative Templates > Google Chrome - Default Settings (users can override)
Both
HKLM\Software\Policies\Google\Chrome\Recommended
Setting the policy to Enabled imports autofill form data from the previous default browser on first run. Setting the policy to Disabled or leaving it unset means no autofill form data is imported on first run. Users can trigger an import dialog and the autofill form data checkbox will be checked or unchecked to match this policy's value.