Chinese Pie is a Quebecois dish that was brought to New England cities where French-Canadians came to work in the mills. It has cheap, tasty ingredients and so caught on for school lunches, especially with ketchup. I believe it has spread to the rest of the country by now. I always wondered what the heck the Chinese had to do with the dish, as the potato and corn are New World foods, and beef is less-often used in China.
When the Canadian railroads were being extended westward, there were English owners and bosses who hired Chinese cooks. They wanted Shepherd's pie, but lamb (or even mutton) was harder to get, and the proper vegetables such as peas and carrots were in less supply as well, so beef and corn it was. The French Canadian workers loved it and brought it home. It came to New England soon after.