Preheat oven to 400°F.
Add chopped carrots, chopped onion, and potatoes to the bottom of a Dutch oven. Drizzle lightly with olive oil and sprinkle with salt and pepper.
Pat the chicken dry with paper towels. Season generously all over (including inside the cavity) with salt, pepper, paprika, and Italian herbs.
Stuff the cavity with 1 lemon cut in half and ½ an onion.
Place the chicken on top of the vegetables.
Cut the second lemon in half. Squeeze the juice over the chicken, then place the squeezed lemon halves into the pot.
Drizzle olive oil over the chicken.
Cover and roast for 45 minutes.
Remove the lid and roast another 30–45 minutes, until the internal temperature reaches 165°F in the thickest part of the thigh and the skin is golden brown.
Let rest 10–15 minutes before carving.
Serve with the roasted vegetables and creamy mashed potatoes. Spoon the pan juices over everything before serving.