Everything running in a browser is sometimes a challenge when it comes to conflicting keyboard shortcuts between browsers and terminal applications. Luckily the ChromeOS terminal is quite configurable.
Hit ´´Ctrl+Shift+P´´ to go to settings and then paste the following in “Keyboard bindings/shortcuts”
{
"Alt-187": "PASS",
"Alt-189": "PASS",
"Alt-219": "PASS",
"Alt-221": "PASS",
"Ctrl-Shift-W": "PASS"
}
Thanks to this Reddit post for the hint.