Preheat oven to 350 degrees. In a buttered casserole dish. Combine chicken, cooked rice and green beans. In a saucepan melt butter over medium high heat. Stir in onions and cook for 1 minute. Stir in flour and cook for 1 minute. Whisk in chicken stock and bring to a simmer. Whisk in cream or milk and return to a simmer. When sauce has thickened pour over mixture in casserole dish. Sprinkle with parmesan and almonds and bake for 30 minutes.