UPDATE: new function found!
var setScroll = function(i) {
if($(i).length>0)
$(i).niceScroll().updateScrollBar();
}
Call this function to Update niceScroll
setScroll(".classWithNiceScroll");
-----Old Method-----
use this instead of resize
$("idORclass").getNiceScroll().remove()
$("idORclass").nicescroll();