Nels sits next to 5 phonetic neighbors — Neil, Niels, and Nels are the closest matches by sound. Most share Nels's Scandinavian cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"champion, cloud"
"from the Cayman Islands"
"fortress, military camp"
"open grassy plain"
"woodland settlement"
"firebrand, son of Tye"
"enduring, steadfast"
"God has heard (from Ja-/Jacob root) + spirit of battle (from Kayden)"
"angelic, messenger"
"God will establish, God raises up"
"edge of a shield"
"comfort, ease, happiness"
"oak grove"
"Yahweh has shown favor"
"vision of God"
"anointed one who carries"
"little slender one"
"he enlightens"
"courageous, valiant"
"settlement by the woodland grove"
"of Devon, creative modern coinage"
Similar sound: These names share phonetic patterns with Nels — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Irish Gaelic via Scandinavian origins, giving them the same cultural heritage as Nels.
Rhythm: Nels is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.