Sift flour, sugar, baking powder, and salt together in a bowl. Beat egg into milk in a separate bowl until thoroughly combined.
Pour melted butter into flour mixture; whisk in milk mixture to make a smooth batter. Fold chocolate chips into batter.
Heat a small nonstick skillet over low heat; pour about 1/3 cup of batter into hot skillet and cover with a lid. Cook pancake until browned on the bottom, about 3 minutes; flip pancake and cook covered until other side is browned. Repeat with remaining batter.
