Step 1: Preheat oven to 400°F (200°C). Pierce sweet potatoes with a fork and bake for 45-50 minutes until tender.
Step 2: While potatoes bake, combine cranberries, apple, brown sugar, cinnamon, and nutmeg in a saucepan. Cook over medium heat for 8-10 minutes until cranberries burst and mixture thickens.
Step 3: Let potatoes cool slightly, then slice in half lengthwise and scoop out flesh, leaving a 1/4-inch shell.
Step 4: Mash potato flesh with melted butter, milk, and salt until smooth.
Step 5: Fold cranberry-apple mixture and pecans into mashed potatoes.
Step 6: Spoon filling back into potato shells and place on baking sheet. Bake at 375°F (190°C) for 15-20 minutes until golden.