Yeah, since they didn't mention 4Kids, they'll probably use the other English dub. That might be the better choice since they might not be able to get the 4Kids voice cast for the seasons that they're producing. I am surprised that they're just going to air specials for the first two seasons. That seems pretty weird. Though, hopefully, it's just an introduction and they'll eventually air the whole first two seasons.
My guess as to why Nick wanted Winx Club is that they want a more girl-centric cartoon series. They have a good amount of shows that appeal to boys and some gender-neutral series, like iCarly, but outside of Dora the Explorer, I can't think of a cartoon show that aims directly at girls. Plus, it might be a way to attract some of the older girls who aren't into Dora anymore, but still like fantasy/fairy tale like elements. I do agree that Nick going after Huntik would have been a better fit, overall, not to mention really awesome.