Unfortunately Chromebook’s don’t have a ‘delete’ key. So how can you delete a forward letter as you do in windows PC?
The ‘backspace’ key will remove letters to the backward direction only.
However, to delete the forward letters all you may have to do is to press and hold the ‘alt’ key located to the left of the space bar and and then press the ‘backspace’ key. That’s how I am doing the delete job in my chrome PC. Give it a try, you will be habituated after few deletes.