• Preheat oven to 400˚F. Halve spaghetti squash lengthwise and scrape out seeds; drizzle cut sides with 1 tbsp olive oil and season with 1/4 tsp each salt and pepper. Bake, cut sides down, on parchment paper–lined baking sheet for 45 to 50 minutes or until tender. Let cool slightly. Using a fork, scrape strands of squash into bowl; reserve squash shells.
• Meanwhile, heat remaining oil in skillet set over medium-high heat; cook chicken, onion, and remaining salt and pepper for about 5 minutes or until chicken is browned. Stir in pesto; bring to simmer. Cook for about 5 minutes or until chicken is cooked through. Stir in cherry tomatoes; cook for about 1 minute or until slightly softened.
• Toss spaghetti squash with chicken mixture; divide among reserved squash shells. Top with mozzarella cheese; broil for 1 to 2 minutes or until cheese melts. Sprinkle with chopped basil.

Tip: Add chopped black olives or jarred artichokes for a savory addition.