Nanna sits next to 3 phonetic neighbors — Anna, Nana, and Hannah are the closest matches by sound. Most share Nanna's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"Daring, brave"
"pledged to God, God is my oath"
"king"
"Noble and famous"
"to soothe, to comfort"
"star"
"narcissus flower, sleep-inducing"
"the white, noble one"
"bright like a bear"
"gentle, mild"
"settlement of the Britons"
"free one, of the Franks"
"bright, clear, famous"
"beautiful one"
"champion"
"king; royalty"
Similar sound: These names share phonetic patterns with Nanna — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old Norse origins, giving them the same cultural heritage as Nanna.
Rhythm: Nanna is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.