Nicklaus sits next to 4 phonetic neighbors — Nicholas, Nicolas, and Niklas are the closest matches by sound. Most share Nicklaus's German-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"victory of the people"
"joy, song of life"
"elm grove"
"venerable, worthy of reverence"
"instrument of God"
"devoted one"
"from the forest"
"from the settlement near St. Botolph"
"God is gracious"
"fair warrior, white hero"
"the writer, the recorder"
"first light"
"the wind"
"from Hesston (place name)"
"sunny, bright, cheerful"
"servant, messenger"
"brave man of power"
"graced by God"
"sand hill, sandy mound"
"independent, nonconformist"
Similar sound: These names share phonetic patterns with Nicklaus — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Nicklaus.
Rhythm: Nicklaus is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.