Chimichurri Roast Chicken

Place oven racks in top third and bottom third of oven. Preheat oven to 450 degrees F. Line 2 rimmed sheet pans with parchment paper. Add potatoes and carrots to sheet pan. Rinse chicken and pat dry with paper towels; add chicken pieces to second sheet pan, skin side up. Drizzle both pans with olive oil and massage into chicken and vegetables. Season with salt and pepper on all sides. Place vegetables on bottom rack and chicken on top rack. Roast until internal temperature of largest breast piece reads 165 degrees F, 25 to 30 minutes. Set oven to broil and cook until skin is crisp and golden brown, 5 minutes more. Remove chicken from oven to rest. Move vegetables to top rack and broil 5 minutes. Meanwhile, in a small food processor, combine parsley, cilantro, onion, garlic, 1 teaspoon salt, red pepper flakes, and vinegar. Pulse a few times and scrape down sides of the bowl. While motor is running, drizzle in 1/2 cup olive oil and process until almost smooth. Transfer chicken and vegetables to a large platter and sprinkle with sea salt. Top with about 1/2 cup of chimichurri sauce and serve remaining sauce in a bowl.