A side of rainbow chard brings iron as well as vitamins A, C, and K.
Separate stems and leaves of rainbow chard. Thinly slice stems crosswise and cut leaves into 1-inch strips.
Heat oil in a medium Dutch oven or saucepan over medium. Add onion and chard stems; cook, stirring occasionally, until softened, about 5 minutes. Add chard leaf strips and cook, stirring constantly, until slightly wilted, about 3 minutes. Stir in vegetable broth, salt, and pepper; bring to a boil over medium-high. Reduce heat to medium, and cover. Cook, undisturbed, until tender, about 8 to 12 minutes. Remove from heat, and stir in vinegar.
Divide braised rainbow chard among 8 bowls and top with crispy garlic chips. Serve immediately.
Rainbow chard can be prepared up to 3 days in advance and stored in an airtight container in refrigerator; reheat and garnish right before serving.