In a large pot, heat olive oil over medium heat. Add onion, carrot and salt. Cook until they just start to brown, about 9 minutes. Add garlic and red pepper flakes, cook until they get fragrant, about 15 seconds. Add chickpeas, cranberries, broth, and put chard on top. Cover, cook until the chard is wilted, about 9 minutes, stirring often. Uncover and cook until the liquid cooks away, about 5 minutes. Optionally serve with lemon wedges.