Preheat the oven to 350°F and set aside 3-4 lined baking sheets.
In a medium-sized bowl, whisk the flour, baking soda, salt, and cornstarch. Set aside.
In a large bowl or the bowl of a stand mixer fitted with the paddle attachment, add the butter, brown sugar, and sugar. Beat with a hand mixer or the stand mixer until light and fluffy.
Add the milk and vanilla and beat again until smooth.
Add about half of the flour mixture into the wet mixture and mix until just barely combined. Add the remaining flour mixture and mix until just combined.
Fold in the chocolate chips and macadamia nuts.
Scoop out ~1.5 tablespoon-sized balls of dough and place on the baking sheets, leaving about 2" in between each.
Bake for 9-11 minutes, until slightly golden. Allow to cool on the baking sheets, then enjoy.
