Preheat oven to 350°F (175°C). Line a 9×5-inch loaf pan with parchment paper.
In a small bowl, mix flaxseed and warm water. Let it sit for 5 minutes.
In a large bowl, whisk together pumpkin purée, sugar, oil, plant milk, vanilla, and flax egg.
Add flour, baking powder, baking soda, salt, and pumpkin spice. Stir until just combined.
Fold in chocolate chips.
Pour into the loaf pan, smooth the top, and sprinkle extra chips.
Bake for 55–60 minutes, or until a toothpick comes out clean with a few moist crumbs.
Cool 15 minutes in the pan, then transfer to a rack before slicing.