Have you tried making a .vbs file to set chromeChrome as the default browser automatically?
Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.Run "%windir%\system32\control.exe /name Microsoft.DefaultPrograms /page pageDefaultProgram\pageAdvancedSettings?pszAppName=google%20chrome"
WScript.Sleep 1200
WshShell.SendKeys "{TAB}"
WshShell.SendKeys " "
WshShell.SendKeys "{TAB}"
WshShell.SendKeys "{TAB}"
WshShell.SendKeys " "
WScript.Quit
Reference in the article's comments: http://ccmexec.com/2015/09/making-ie-the-default-browser-in-windows-10-during-osd/ comment by user "Raz" in Making IE the default browser in Windows 10 during OSD