Preheat oven to 350 degrees F (175 degrees C). Grease a baking pan.
Mix flour, baking soda, and salt together in a small bowl.
Cream butter, white sugar, and brown sugar together in a large bowl with an electric mixer. Add milk, eggs, and vanilla extract. Stir in flour mixture; fold in chocolate chips and oats. Spread into the prepared baking pan.
Bake in the preheated oven until top is golden brown, about 30 minutes.
