Preheat oven to 350 degees F. Line fifteen 2-1/2-inch muffin cups with paper bake cups or grease muffin cups; set aside.
Combine flour, sugar, baking powder, baking soda, salt and cinnamon in medium bowl.
In another medium bowl, combine eggs, pumpkin, and oil. Add all at once to flour mixture; stir just until moistened. Fold in pecans and chocolate pieces. Spoon batter into prepared muffin cups, filling each about two-thirds full.
Bake for 20 to 25 minutes or until toothpick inserted near centers comes out clean. Cool in muffin cups on wire rack for 5 minutes. Remove from muffin cups. Cool on wire rack. Tint frosting as desired; spread over cupcakes. Top with multicolor sprinkles. Makes 15 servings.