Sorry, I know this doesn't directly answer your question but can help you achieve what you are trying to achieve. What functionality are you trying to achieve by using the niceScroll plugin?
If it is smooth scrolling on anchor tags, you can do this:
$(function() {
$('a[href*=#]:not([href=#])').click(function() {
if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'') && location.hostname == this.hostname) {
var target = $(this.hash);
target = target.length ? target : $('[name=' + this.hash.slice(1) +']');
if (target.length) {
$('html,body').animate({
scrollTop: target.offset().top
}, 1000);
return false;
}
}
});
});
http://css-tricks.com/snippets/jquery/smooth-scrolling/
else if it for softening the scroll effect when scrolling down a page, you can do this:
$(document).ready(function() {
var page = $('#content'); // set to the main content of the page
$(window).mousewheel(function(event, delta, deltaX, deltaY){
if (delta < 0) page.scrollTop(page.scrollTop() + 65);
else if (delta > 0) page.scrollTop(page.scrollTop() - 65);
return false;
})
});
jquery vertical mousewheel smooth scrolling
Both solutions are cross-browser compatible.