Preheat oven to 350 degrees F. Heat oil in a medium saucepan over medium-high heat. Add onion and garlic; cook, stirring occasionally, until the onion is translucent, 4 to 5 minutes. Add quinoa; cook, stirring occasionally, for 30 seconds. Add water; increase heat to high and bring to a boil. Reduce heat to medium; cover and cook for 15 minutes. Remove from heat; let stand, covered, for 5 minutes. Stir in chicken, marinara, Parmesan and 1/2 cup basil.