Butter an 8-by-8-inch baking pan or similarly sized gratin dish. Layer one third of the potatoes in the dish and top with 1/8 teaspoon each salt and pepper, a third of the cheese, and half the Canadian bacon. Spread the Swiss chard in a single layer. Top with half the remaining potatoes and sprinkle with 1/8 teaspoon each salt and pepper. Spread half the remaining cheese and the remaining Canadian bacon over the potatoes. Add the remaining potatoes to the dish, sprinkle with the remaining 1/8 teaspoon each of salt and pepper, and top with the remaining cheese and 1 tablespoon butter. Pour the chicken broth over all.