Heat waffle iron according to manufacturer's instructions.
In a medium bowl, mix pumpkin, milk, eggs, butter, and vanilla until combined. Set aside.
In a large bowl, whisk together flour, sugar, baking powder, salt, and pumpkin pie spice.
Add wet ingredients to dry ingredients.
Stir until combined.
Spray waffle iron with cooking spray.
Ladle batter into waffle iron, filling forms completely.
Close lid and cook until light golden brown.
Repeat steps until no more batter remains.
Dollop with Chantilly cream and sprinkle tops with candied pepitas.