Preheat oven to 450°F. Trim chicken of any excess skin.
In a small bowl, combine 2 teaspoons kosher salt, the cumin, oregano, and cayenne pepper, and set aside.
Add 2 tablespoons olive oil to a large 17-inch baking sheet. Add the sweet potatoes and chicken and toss to coat them in the oil. Sprinkle with the seasoning mixture.
Place the baking sheet in the oven and roast (with the chicken skin side up) for 10 minutes.
Reduce the oven temperature to 425°F and add the broccolini and tomatoes, tucking them between the chicken and sweet potatoes. Drizzle with the remaining olive oil and 1 teaspoon of salt.
While the chicken roasts, make the cilantro cashew pesto by combining the pesto ingredients in a blender or food processor. Blend until smooth and transfer to a measuring cup or other container with a pourable spout.
Continue roasting for approximately 15 minutes, or until the chicken registers 165°F in the thickest part with an instant-read thermometer and the vegetables have softened and are slightly charred.
Spoon or drizzle the cilantro cashew pesto over the chicken and vegetables and serve.