Cant add the URL to my youtube channel Doesn’t let me save it

Can you be more specific? Do you mean you can't add nightbot as a moderator to your channel?
Just copy this: https://www.youtube.com/channel/UCSvjQBDgYDB5TGVmCZObcwA
And add it to your moderators.

it depends on what your working on if it is a laptop or a desktop possibly a iPad you would need to make sure you are copying it correctly if you are on laptop or desktop just press the Ctrl and c button after highlighting it or if you are on a non-keyboard device like a iPad you have to double tap on the begging of the link the drag you finger to the last part of the link then tap on the link it should pop up above the link saying copy click that and the double tap and hit paste on the screen and you should be all set.