@glacier_bear_82 is right.There are 829 bearers of this name in Spain (source: Instituto Nacional de Estadística).However, in Spanish, this name is more used as a diminutive of Natalia.https://www.conmishijos.com/nombres/natacha/(in Spanish, it mentions Natacha as a diminutive of Natalia)
This is also the Portuguese form of Natasha. It first arose in the late 1960s and was most popular in 1975 (though just outside the top 100). Regarding its usage in recent years, it was given to 26 baby girls in 2011, but has since dropped to a birth count of 16 in 2014. [noted -ed]Sources: Instituto dos Registos e do Notariado via Nomes a mais Nomes (nomesportugueses.blogspot.pt) and SPIE (www.spie.pt - data represents 8.2 million adults, not a full representation of Portuguese adult and elderly population).
Spanish Pronunciation: na-TA-cha
You'll find numerous bearers on Social Media.