Toss kale with the olive oil, seasoned salt, and nutritional yeast.
Place the kale in the basket of an air fryer at 370 degrees for 5 minutes. Do not overcook or the kale will become bitter. Crumble the kale into a bowl.
To make the popcorn using a microwave popcorn popper, pour the oil and kernels in the popper. Cover and pop for 4 minutes. If using a pot, follow the same method, but place the pot over medium heat and cover. Cook for about 5-8 minutes, monitoring the pot closely. When the popping noise of the kernels slows, remove from the heat.
Place the popcorn in a bowl. Melt the Earth Balance butter and pour over the popcorn. Immediately sprinkle the kale dust on top, and mix thoroughly and vigorously. You want the kale to stick to the popcorn.
Serve in bowls and sprinkle any remaining kale crumbs on top.