How to Make It
Heat oven to 450° F. On a large rimmed baking sheet, toss the chicken and tomatoes with 2 tablespoons of the oil, ½ teaspoon salt, and ¼ teaspoon pepper. Roast until the chicken is cooked through, 30 to 35 minutes.
Meanwhile, heat the remaining tablespoon of oil in a large skillet over medium-high heat. Add the onion and ¼ teaspoon each salt and pepper and cook, stirring frequently, until softened, 4 to 6 minutes. Add the collard greens and cook, tossing frequently, until tender, 5 to 7 minutes. Serve with the chicken.