Preheat the oven to 425°F (218°C) and place the oven rack in the center position. Line a 9" x 5" loaf pan with parchment paper.
In a large bowl, whisk together 2 cups all-purpose flour, 2 teaspoons baking powder, ½ teaspoon baking soda, and 1 teaspoon salt.
In a medium bowl, whisk together 1 cup granulated sugar, ½ cup avocado oil, 1 tablespoon vanilla extract, ½ cup sourdough discard, ¾ cup sour cream, ¼ cup milk, and 2 large eggs.
Pour the wet ingredients into the dry ingredients and mix together until smooth. Do not over mix. Using a spatula, fold in 1 ½ cups semi-sweet chocolate chips until they are evenly distributed in the batter.
Pour the batter into the loaf pan and lower the oven temperature to 350°F (176°C) and bake the loaf for 45-60 minutes. Check for doneness with a toothpick around 45 minutes. If the top is browning too quickly, tint with aluminum foil and continue baking until a toothpick comes out clean.
Remove the loaf from the oven and allow it to cool completely in the loaf pan before slicing.