Preheat your oven to 180°C and line a 9x9 baking pan
In a large bowl, combine the flour, rolled oats, salt, and baking powder. Add in the nut butter, maple syrup, eggs, milk, vanilla extract, and mix until fully combined.
Fold in the chocolate chips and pour the batter into the prepared baking pan, spreading it out evenly with a spatula.
Bake for about 12 minutes, or until the edges are golden and a toothpick inserted into the centre comes out clean.
Let cool slightly, then sprinkle with flaky sea salt and cut into 9 bars.