Since nn are not registered like the formal name. But maybe you just mean "well known" nick names?
Elizabeth has so many nn, so I don't find
Beth the "official one". It could just as well be
Ellie,
Liza,
Lizzie,
Libby,
Bessie,
Betty,
Betsy etc.
Lisa,
Lissa and Bettan are the most popular ones in Sweden.
And there must be nn which can be used for more than one formal name. Like
Josie for both
Josephine and
Jocelyn.
"You sought a flower and found a fruit. You sought a spring and found a sea. You sought a woman and found a soul. You are disappointed." (
Edith Södergran 1891-1923)