var x = 0;

expect(function() { x += 1; }).to.change(function() { return x });
expect(function() {     }).not.to.change(function() { return x });

//main.js:
requirejs.config({
  paths: {
     'chai' : 'chai'
  ,  'chai_change': 'chai-change'
  }
, shim: {
  ,  'chai_change' : ['chai']
  }
});

//file.js
define([
  'chai'
, 'chai_change'
], function(chai){

  //I know this should work because I'm also using chai-things, sinon-chai and chai-jq and they work fine.
  chai.use(require('chai_change'));
});