Naoko (直子) combines nao (honest, straight) and ko (child) — "honest child" or "upright child."
Naoko Takeuchi (born 1967) is the Japanese manga artist who created Sailor Moon.
Naoko does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Naoko reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.