Preheat the air fryer to 325 degrees F for 5 minutes.
In a bowl, whisk together the flour, baking powder, salt, pumpkin pie spice and sugar.
Combine the pumpkin puree, egg, vanilla extract, milk and oil in a separate bowl and mix.
Pour the wet ingredients into the dry ingredients and mix together until fully incorporated. Do not over mix.
Melt the butter for the streusel topping in the microwave in 20 second intervals.
In a separate bowl, mix together flour, brown sugar, pumpkin pie spice, chopped pecans and melted butter to make the pecan streusel topping.
Spray cupcake liners with non stick cooking spray and place them into the muffin pan.
Use a cookie scoop to add the pumpkin muffin batter into the cupcake liners. Fill each liner about 3/4 of the way full.
Add about 1 tbsp or more of the streusel topping to the top of each muffin. Use a spoon to press the topping down a bit to ensure it nestles into the batter.
Transfer the pumpkin spice muffins to the air fryer and cook at 325 degrees F for 12-15 minutes or until a toothpick inserted into the center of the muffin comes out clean.
Allow the muffins time to cool down a bit at room temperature before enjoying.