Preheat oven to 375℉. Line a large rimmed baking sheet with parchment paper.
In a large bowl, whisk together the oat flour, baking soda and salt. Next, whisk in the brown sugar and white sugar. Add in the olive oil, milk, vanilla and mix together until combined. Fold in the chocolate chips and walnuts (I had to use my hands). Chill the dough for 30 minutes. Form into balls (about 2 tbs each cookie), space them out on the tray because the cookies will spread, and bake for 8-9 minutes. Remove from oven and allow the cookies to set on the tray for 10 minutes before moving them to the cooling rack. Top with flaky sea salt!