Preheat the oven to 350 degrees Fahrenheit and spray the bottom and sides of a standard 9 x 5” loaf pan with cooking spray and set aside.
In a large bowl whisk together the dry ingredients including the flour, baking powder, salt, soda, cinnamon, and nutmeg and set aside.
In a stand mixer or in a separate large bowl with a whisk, combine the pumpkin, eggs, and sugars until smooth. Add the olive oil and mix until combined. Add the dry ingredients and mix until just combined- do not overmix.
Using a spatula spread the batter into the loaf pan. Bake for 70-80 minutes, until toothpick inserted in the center comes out clean. Allow to cool in bread pan for 10 minutes, then invert onto cooling rack and let cool completely.
Make the glaze by whisking together the powdered sugar and milk. If too thick, add additional milk, ½ Tablespoon at a time. Drizzle the glaze over the top of the loaf and sprinkle pistachios on top of glaze. Let sit for 10-15 minutes to set before serving.