Easy Clam Chowder with Green Chilies

Name: Easy Clam Chowder with Green Chilies
Ingredients: 10 small red potatoes (sliced into coins); 1 cup carrots (diced); ½ cup onions (finely diced, divided); ½ cup celery (finely diced); 32 oz clam juice; ½ cup chicken broth; ½ cup green chilies (we used 3 Hatch chilies); ½ tsp dried basil; ½ tsp dried thyme; ½ tsp dried oregano; 2 tsp salt; ¼ tsp ground black pepper; ½ cup butter (1 stick); ⅓ cup all-purpose flour; 2 cups half and half; 18 oz canned clams (rinsed, drained, and minced)