However, it should be noted that crossing the border area on foot is a complicated task, which requires a legal border pass and a Chinese visa. In addition, due to political, geographical and climatic reasons, such a trip also needs detailed research and planning. I suggest you consult a professional hiking company or relevant embassy or consulate for more accurate and detailed information.
In a word, hiking from Nepal to China needs careful planning and preparation, and make sure that you have a legal pass to ensure a smooth and safe journey.