Preheat oven to 425°F with rack in upper third position.

Place chicken on a plate; sprinkle evenly with 2 teaspoons salt and ½ teaspoon pepper. Let stand at room temperature for 30 minutes. (Alternatively, refrigerate, uncovered, for up to 8 hours.)

Stir together chili crisp, vinegar, 1 tablespoon olive oil, and 2 teaspoons honey in a small bowl until combined. Set aside.

Toss together sweet potatoes, Broccolini, 2 tablespoons chili crisp mixture, and remaining 1 tablespoon olive oil, ¾ teaspoon salt, and ½ teaspoon pepper in a large bowl until evenly coated.

Arrange potatoes in an even layer on a large rimmed baking sheet; reserve Broccolini in bowl. Place seasoned chicken, skin side up, on top of sweet potatoes.

Roast chicken and sweet potatoes for 25 minutes.

Remove from oven, and arrange reserved Broccolini around chicken.

Roast at 425°F until vegetables are tender and an instant-read thermometer inserted into thickest portion of chicken registers at least 175°F, about 10 more minutes.

Meanwhile, stir remaining 3 teaspoons honey into chili crisp mixture in small bowl.

Remove baking sheet from oven. Increase oven temperature to broil.

Brush chicken with half of chili crisp mixture. Broil until chicken is crisp and charred in spots, 2 to 4 minutes.

Remove from oven, and brush chicken with remaining chili crisp mixture.

Garnish with scallions, and serve.