In pot, cook garlic in oil over medium until softened, about 4 minutes. Add stock, Parmesan rind (if using), and carrot. Simmer until carrot softens, about 8 minutes. Add tortellini and zucchini. Cook until a few minutes shy of al dente, about 5 minutes. Add chard and peas. Cook until chard wilts, about 3 minutes; season. Discard rind (if using).
