01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt until thoroughly mixed.
03 - In a separate bowl, whisk eggs, milk, melted butter, and vanilla extract until smooth.
04 - Pour the wet ingredients into the dry ingredients and stir gently until just combined, maintaining a slightly lumpy batter without overmixing.
05 - Fold in chocolate chips and, if desired, the optional chopped nuts until evenly distributed.
06 - Spoon batter evenly into prepared muffin cups, filling each about three-quarters full.
07 - Bake for 18 to 20 minutes until a toothpick inserted into the center comes out clean or with minimal crumbs.
08 - Allow muffins to rest in the pan for 5 minutes, then transfer to a wire rack to cool completely.