白切鸡 and
白斩鸡 are essentially the same dish — a Cantonese whole chicken poached in lightly seasoned water, chilled, and chopped for dipping in ginger-scallion oil or soy.
白切 emphasizes the cutting step;
白斩 emphasizes the chopping.
白切鸡 is more common in Guangdong,
白斩鸡 in Shanghai and Zhejiang.