Nixon sits next to 4 phonetic neighbors — Dixon, Mason, and Jackson are the closest matches by sound. Most share Nixon's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of Nicholas, son of Nick"
"army ruler, power of the army"
"son of Otto"
"crooked mouth, wry-mouthed"
"God's peace, divine peace"
"high stronghold, fort on the headland"
"divine reward (alternate interpretation)"
"surname origin unclear, possibly from place name"
"faith, pledge"
"wise friend"
"river, great water (from Zaire)"
"olive tree"
"son of the firebrand (short for Tyson)"
"enlightenment, calm clarity"
"rock, harmony"
"son of Aodh (fire)"
"passionate, earnest"
"God supports, Yahweh supports"
"defender of men"
"fire (from the sun god Aodh)"
Similar sound: These names share phonetic patterns with Nixon — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have English origins, giving them the same cultural heritage as Nixon.
Rhythm: Nixon is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.