Beat egg with sugar until thick. Stir in melted butter and banana extract. Sift flour and baking powder. Mix into batter. Batter will be thick.
Preheat pizzelle griddle. Lightly grease griddle as needed. Drop 1 tablespoon batter onto each circle. Cook for approximately 25 seconds.
Once the pizzelles are done, set aside. Melt milk chocolate chips in microwave on medium setting for approximately 1 1/2 minutes. Stir chocolate until it is smooth. Spread melted chocolate about 1/2" strip around the edge of a pizzelle. Sprinkle chopped pecans over chocolate before it hardens. Set aside to cool and harden. Repeat with the remaining pizzelles.
Optional: If you would like your pizzelles to look more "dressy," drizzle the tops of the pizzelles with melted white chocolate.