Some nicknames can stand alone.
And many people don't use nn at all, it is not necessary for everyone to have a nn. Here in Sweden, former nn are often used as formal names, like
Olle (former nn of
Olof) or
Kajsa (former nn for
Karin which is a former nn for
Katarina). And we don't think they have an informal areas towards everything. Sometimes you read to much into a name!
"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."
"It does not become me to make myself smaller than I am." (
Edith Södergran 1891-1923)