Heat oven to 325. Cook and drain tortellini as directed on package. While tortellini is cooking, grease 3 litre casserole. Heat 1 tablespoon oil in a 25 cm skillet over medium high heat. Cook broccoli, onion and bell pepper in oil for about 3 minutes, stirring frequently, until crisp-tender. Remove broccoli mixture from skillet. Cook flour and 2 tablespoons oil in same skillet over low heat, stirring constantly, until smooth. Stir in milk, broth and cumin. Heat to boiling over medium heat, stirring constantly; remove from heat. Stir in chicken, Monterey Jack cheese, the tortellini and broccoli mixture. Spoon tortellini mixture into casserole. Bake uncovered 25 to 35 minutes or until bubbly.
During the last 5 minutes of baking, sprinkle with Colby cheese and tortilla chips; bake until cheese is melted.