Halve squash lengthwise; remove seeds. Bake, cut side down, on a parchment paper-lined baking sheet in a preheated 400°F (200°C) oven until flesh is tender when pierced, about 1 hour. Using a fork, scrape cooked strands from squash flesh into bowl. Toss with half each of the salt and pepper. Cover and keep warm.
Meanwhile, heat a Dutch oven or large wide saucepan over medium-high heat. Add oil; cook eggplants and onion, stirring often, until softened, about 5 minutes. Stir in zucchini, yellow pepper and garlic; cook, stirring occasionally, until softened, about 5 minutes. Stir in tomatoes, chickpeas, hot pepper flakes and remaining salt and pepper; bring to a boil. Reduce heat to medium-low, cover and cook, stirring occasionally, for 20 minutes. Uncover and continue cooking, stirring occasionally, until vegetables are softened and tomatoes form a thickened sauce, about 20 minutes.
Spoon squash onto plates or a platter. Mound ratatouille mixture on top; sprinkle with basil.
Per serving: 214 calories, 7 g protein, 5 g fat (1 g saturated fat), 42 g carbohydrates, 7 g fibre, 0 mg cholesterol, 701 mg sodium