Place green beans in boiling water to cover in a large saucepan, and simmer 3 minutes or until crisp-tender. Drain; rinse with cold water and drain. Set aside.
Cook bacon pieces in a large skillet over medium heat 5 to 7 minutes or until crisp; remove bacon with a slotted spoon, and drain on paper towels, reserving drippings in skillet.
Sauté green beans in hot drippings in skillet 2 minutes or until heated. Sprinkle with cheese, and cook, stirring constantly, 30 seconds or just until cheese begins to melt. Sprinkle evenly with walnuts, salt, pepper, and bacon; serve immediately.