Welcome to the USA... A country built by immigrants (more than 97% of the current population are immigrants or descendants thereof) but which has been making it increasingly difficult for foreigners to live and work in it.
Nika will be able to play regular games in the W once she has a valid visa allowing her to "work" (earn $$), which could be one of several categories: H, E, O, P (with subcategories). AFAIK, the WNBA does not sponsor the most common employment-based work visa (H-1B). On the other hand, she does not need green card status offered by the E visas, which take a long time to process. My guess is that she is waiting for an O-1 (reasonably quick). I am sure the Storm front office is quite versed in this situation (duh!). We just need to wait.