In a saucepan over medium heat,, soften the onion in the oil. Season with salt and pepper. Add the rice and cook for 1 minute, stirring to coat well with the oil. Add the squash and hot chicken broth, about 250 ml (1 cup) at a time, stirring frequently until the liquid is almost completely absorbed between each addition. Cook for 18 to 22 minutes or until the rice is al dente, stirring frequently until the liquid is almost completely absorbed between each addition of broth.