Potato Corn Chowder

Name: Potato Corn Chowder
Ingredients: 2 tablespoons vegetable oil; 1 large yellow onion (peeled and diced); 3 carrots (peeled and diced); 2 celery ribs (diced); 3 cloves garlic (minced); 5 medium red-skinned potatoes (cubed); 6 cups chicken stock; 1/4 teaspoon cayenne pepper; 4 cans (16 oz. each) whole kernel corn (undrained); 1/4 teaspoon Worcestershire sauce; 1 green onion (sliced, plus more for garnish); 4 cups cooked diced ham; 2 cups whole milk; 4 cups shredded sharp cheddar cheese; Salt and pepper to taste