In a large bowl, whisk together the flour, brown sugar, baking powder, and pumpkin pie spice. Whisking here matters because it evenly distributes the baking powder, which keeps your pancakes from rising unevenly. I like to give it a good 20-30 seconds of whisking before moving on.
In a separate bowl, whisk together the milk, vanilla, and egg until fully combined. Doing this in its own bowl first means the egg gets properly incorporated instead of forming little streaks in your final batter. It only takes a minute, so don't skip it.
Pour the milk mixture into the flour mixture and stir until just combined a few lumps are totally fine here. Overmixing at this stage is the number one thing that makes pancakes turn out dense instead of fluffy, so stop as soon as you don't see dry flour.
Gently fold in the pumpkin puree until the batter turns that gorgeous orange color, then fold in half a cup of the chocolate chips. Save the rest for sprinkling on top later. Let the batter rest for a couple of minutes while your griddle heats up.
Preheat your griddle or skillet to medium heat and spray it lightly with non-stick cooking spray. Getting the temperature right here is key too hot and the outside burns before the inside cooks through.
Using a ¼-cup measure or a ladle, scoop the batter onto the hot griddle. Immediately sprinkle a few extra chocolate chips over each pancake so they melt right into the top as it cooks.
Cook until you see bubbles forming on top and the bottom is evenly browned, then flip carefully. Cook the second side until golden and the chocolate chips are melted through. Keep finished pancakes warm in a low oven while you cook the rest