Preheat oven to 375F. Toss potatoes with chicken broth, juice of the lemon, 2 tbsp of olive oil, minced garlic, ¼ tsp salt and ½ tsp oregano in the bottom of a Dutch oven large enough to fit your chicken.
Rub chicken all over with remaining olive oil, and season with remaining salt, oregano and some freshly ground pepper. Stuff the cavity with the halves of the juiced lemons.
Place chicken on top of potatoes. Cover and roast in the centre of the oven for 45 minutes.
Remove lid, and give potatoes around the chicken a little bit of a stir (you'll just want to move them around a little bit). Continue cooking uncovered for another 30-40 minutes or until chicken reaches 165F and potatoes are tender.
If skin hasn't browned enough, place under the broiler for 2-4 minutes.