Cook the couscous according to the packet directions then combine with the oil and set aside.
Place the red onion in a bowl and cover with cold water and leave for 10 minutes then drain well.
In a large bowl, combine the couscous, red onion, tomatoes, pesto and basil leaves, season with salt and pepper to taste and toss well. Pile on to a serving plate and top with the rotisserie chicken pieces and scatter with pine nuts and more basil leaves (optional).
Drizzle with the extra virgin olive oil.