1. Preheat oven to 375°F. Line 2 baking sheets with parchment paper.
2. Season squash and onion with oil, salt and pepper. Spread over lined pans, making sure not to overcrowd the pan. Stir occasionally and continue roasting until golden brown, about 20-30 minutes.
3. Stir in garlic and Swiss chard and roast for an additional 5 minutes until garlic is fragrant and chard has wilted.
4. Garnish as desired.