Preheat oven to 425° F.On a baking sheet, toss the sweet potatoes with 2 tablespoons of olive oil. Season with salt and black pepper. Bake for 10 minutes.In a bowl, toss together 2 tablespoons of olive oil, the chicken, chipotle chili powder, paprika, onion powder, garlic powder, cumin, salt, and pepper. Nestle the chicken around the potatoes. Sprinkle the sesame seeds over each piece of chicken. Bake for 25-30 minutes, until the chicken is cooked through.To make the dressing. Combine all ingredients in a glass jar, whisking until smooth. In a salad bowl, combine the kale and herbs. Drizzle a few tablespoons of dressing over the kale and massage into the greens.Remove the chicken from the oven. Add the greens, the avocado, and crumbled feta. Serve with additional dressing.