Heat the olive oil in a 12-inch high-sided skillet over medium. Add the Swiss chard and sprinkle with the shallots and carrots. Pour the tomatoes evenly over the chard, sprinkle with the sugar, and season with salt and pepper. Pour in 1/2 cup water, bring to a simmer, then cover partially with a lid. Cook until the liquid is almost evaporated and the chard is tender, 15 to 20 minutes. Uncover, transfer the chard to a platter, and pour the vegetables and any cooking liquid over the top before serving.