I dont think there are any nn that I feel work on thier own. I much prefer the full name and if you must, use the nn. However, this mainly is because I am sick of hearing nn for such classic names. As in, I much prefer
Joseph to
Joe,
Nicholas to
Nick,
Michael to
Mike,
Andrew to
Andy or
Drew,
Timothy to
Tim,
William to
Will or
Liam. I like the full names better, especially if its popular.