currently, you need to type the first few characters of a
nickname for it to match. I suggest that the completion
function look for loose matches as well as perfect* matches.
let's say my nickname is __BoredZo. you could type Bor\t, and
the completion would look past the __ and find my nickname.
(of course, if someone had a nickname starting with Bor,
theirs would be picked instead, being a perfect match.)