Place potatoes in a large saucepan and cover with water.
Cover and bring to a boil over medium-high heat; cook for 15-20 minutes or until tender.
Meanwhile, in a skillet, saute chicken in oil for 5-10 minutes or until juices run clear.
Drain potatoes; add to chicken.
Place greens and onion in a serving bowl.
Top with chicken mixture.
Drizzle with dressing; sprinkle with croutons and Parmesan cheese.