Preheat the oven to 350 degrees Fahrenheit.
Coat the inside of a 9-inch by 5-inch loaf pan with nonstick cooking spray and dust it with flour.
2. Combine the flour, baking soda, baking powder, cinnamon, salt, cloves and nutmeg in a medium mixing bowl.
3. Combine the butter and sugar in a large mixing bowl and cream with an electric mixer on medium-high speed until fluffy, about 3 minutes, scraping down the sides of the bowl once or twice as necessary.
4. With the mixer on medium-low speed, add the eggs, one at a time, scraping down the sides of the bowl after each addition.
Stir in the pumpkin purée and vanilla.
Stir in the milk.
5.Turn the mixer to low speed and add the flour mixture, 1⁄2 cup at a time, scraping down the sides of the bowl after each addition.
Stir in the chocolate chips and walnuts.
6. Scrape the batter into the prepared pan and smooth the top with a rubber spatula.
Bake the cake until it is firm to the touch and a toothpick inserted in the center comes out clean, 55 minutes to 1 hour.
Let the cake cool in the pan for 5 minutes, invert it onto a wire rack, and then turn it right side up on a rack to cool completely.
Store uneaten cake in a cake keeper at room temperature for up to three days or in the refrigerator, wrapped in plastic, for up to one week.