Nieke comes probably from
Catharina (
Catharina -> Nine -> Nienke), so it has the same meaning as
Catharina (click on it)
(in case you're Dutch as well, this is what my namebook literally says:
Nine: Friese vleivorm vermoedelijk van Catharina, kennelijk gevormd in de kindertaal)
![](http://tickers.TickerFactory.com/ezt/d/4;10709;109/st/20061205/e/Sinterklaas+%3A%29/dt/6/k/2ca6/event.png)