And until someone posts information about the actress Ta-Tanisha where it is explained how she came up with her name, we will never know for sure. It's clear that
Tanisha as a common given name in the USA comes primarily from that actress, but I have never been able to find out any detailed information about her and her name. The explanations that take it back to a Hausa word are just speculation. This site may well be correct that it's merely a modern diminutive of
Tania, but at the moment that's also unconfirmed. Unfortunately this actress seems to have disappeared from the radar screen so I don't know if we will ever find out the origin of her name.