Wash and peel the sweet potatoes. Cut into ½ inch cubes and place into a bowl.
Add the onion powder, garlic powder, and paprika to the bowl. Toss the sweet potatoes in the seasonings, trying to coat as evenly as possible.
Add the oil and toss to combine.
Place the seasoned sweet potatoes into your air fryer. Cook at 400 degrees F for 13-15 minutes, shaking halfway and checking for doneness around 13 minutes.
Around the 10 minute mark, start making the brown butter sage sauce. Cut the sage leaves into strips. Melt the butter in a skillet over medium heat, swirling around as it melts.
Once the butter is almost melted, add the sage leaves and cook for 2-3 minutes, swirling frequently, until sage is turning darker and butter starts getting brown and smelling nutty. Turn of the heat.
Plate the sweet potatoes and spoon the brown butter sauce over the top. Season with salt and pepper if desired.