Preheat oven to 375degrees. Cut squash lengthwise into quarters; remove and discard seeds. Cut each quarter crosswise into 1/2-in. slices; discard ends. Trim and halve Brussels sprouts., Place squash and Brussels sprouts in a large bowl. Drizzle with oil; sprinkle with salt and pepper and toss to coat. Transfer to two foil-lined 15x10x1-in. baking pans. Roast 30-35 minutes or until vegetables are tender, stirring occasionally., Meanwhile, in a dry large skillet, toast pecans over medium-low heat 6-8 minutes or until lightly browned, stirring frequently. Add syrup and butter; cook and stir until butter is melted., Sprinkle vegetables with pecan mixture; gently toss to combine.