Turn the Ninja Foodi on high sear/sauté and add in the butter. When the butter is about half melted, add the chocolate chips on the side. Stir and melt the chips until about 75% are melted and turn the Foodi off. Continue to stir to cool the chocolate down.
Add in the sugar and oil, stir to incorporate.
Lightly beat the eggs and while stirring the brownie batter, slowly pour the eggs into the batter. Stir constantly until the eggs are incorporated. Add in the vanilla extract and stir
Sift in the unsweetened cocoa powder and stir to incorporate. Sift in the flour ⅓ at a time and stir between each addition.
Put the pressure lid on and turn the valve to VENT. Select the slow cook function on high for 4 hours.
You can scoop out the brownies if you want warm and gooey or put the Tender Crisp lid down for 8-10 minutes on Air Crisp at 375° to get that flaky top. Cool and serve.