Natasa is from the Serbian Nataša (Наташа) — Serbian / South Slavic rendition of Natalia (Christmas-born). Natasa is one of the Serbian + Croatian feminine names of the 20th + 21st century.
Natasa 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 Natasa reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.