Toast walnut pieces in a small pan or toaster oven until lightly browned. Remove from heat and cool.
Place a large pot of water on to boil. When it comes to rolling boil, salt the water and cook tortellini to package directions.
Heat 1 cup chicken stock or broth to a boil and remove from heat.
Using a food processor, working in batches, grind spinach leaves with nuts, chicken stock, and garlic. Transfer ground spinach nut paste to a large bowl. Stir in the cheese, nutmeg, and olive oil, and season with salt and pepper, to taste.
Coat hot, cooked tortellini with sauce, tossing in the bowl you prepared sauce in. Turn pasta out on to a serving platter and garnish with a few baby spinach leaves and edible flowers.