Preheat air fryer to 350F then peel & slice the plantain with a mandolin slicer as thin as possible. Mix the plantain, coconut oil, salt, and pepper.
Lay the plantain slices in the air fryer in a single layer. Cook at 350 F for 9 - 11 minutes or until golden brown and crispy. Repeat until all slices have been cooked.
While your plantains are in the air fryer, mash your avocado in a bowl. Dice the tomato and onion, then add them to the mashed avocado. Season with salt and pepper.
Let the chips cool for a few minutes, then serve with your avocado dip.