The line you added was overridden. From man sudoers:
When multiple entries match for a user, they are applied in order. Where there are multiple matches, the last match is used (which is not necessarily the most specific match).
In your case nicholsonjf was a member of the group sudo so for him this line applied:
%sudo ALL=(ALL:ALL) ALL
If you want to override entries in /etc/sudoers just put the new entries after them.
The new entry should look like
myuser ALL=(ALL) NOPASSWD: ALL for a single user, or
Best Answer
No. It'll work with the next
sudo
command.But if it does not work, you can avoid rebooting by running