Place the kale into a large mixing bowl, and drizzle with the olive oil. Toss until evenly coated, then sprinkle with the chili powder and kosher salt, and toss again. Spread the seasoned kale onto a baking sheet.
Roast in the preheated oven for 5 minutes, then stir the kale, and continue roasting until the edges become brown and a little crispy, 5 to 8 minutes. Serve immediately.
