Do not understand why this will not work … it seems simple way. but not in a single command
$(eval var r = false; if('$(querystring $(1))' == 'add') r='$(urlfetch http://ringvig.online/script/nametag.php?add=1&channel=$(channel)&game=$(twitch $(channel) "{{game}}")&name=$(querystring))'; else if('$(querystring $(1))' == 'del') r = '$(urlfetch http://ringvig.online/script/nametag.php?del=1&channel2=$(channel)&game=$(twitch $(channel) "{{game}}"))'; if(r) '' + r + ''; else 'Du skal vælge om du vil add el. del et gametag.';)
This is because Nightbot will only replace up to 2 levels of variables nesting. What you can try is replace every instances of $(channel) with your channel name and see if that fixes the problem. If it doesn’t you’ll have to use an alias command, I can help with that if you need, hopefully. But first, let me know if my suggestion works or not.