Creamy Chicken and Broccoli Stuffed Shells

Name: Creamy Chicken and Broccoli Stuffed Shells
Ingredients: 1 dash olive oil; 1 head broccoli, cut into bite sized florets; 1 onion, diced small; 2 cloves garlic, minced; 6 fresh sage leaves, coarsely chopped; 1 pound boneless, skinless chicken, diced small; 1 pinch salt; 1 pinch freshly cracked black pepper; 1/3 cup white wine; 6 tablespoons butter; 6 tablespoons all-purpose flour; 3 cups milk; 1 tablespoon Dijon mustard; 1 pinch nutmeg; 25 jumbo pasta shells; 8 ounces smoked white cheddar cheese, freshly grated