Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large bowl, combine the oats, flour, sugar, baking powder, salt, chocolate chips and walnuts.
When the oven is heated, add the oil and plant-based milk to the dry ingredients and mix well.
Form the dough into balls. You can use a cookie or ice cream scoop, I just get in there with my hands and press the dough together into balls. You can make them as big or small as you like. I generally get about 10 cookies from this recipe.
Place the balls on the prepared baking sheet and gently flatten them with the palm of your hand.
Bake for 20 minutes, or until they no longer appear wet on top and the bottoms are beginning to turn golden brown.
Remove from the oven and let cool on the pan.