Cook the beans as directed on the package.
In a large saucepan, melt the butter over medium-high heat. Stir in the onion, carrots, celery and crushed garlic and saute for a few minutes, until onions turn clear. Quickly stir in the flour and let cook until slightly browned. Remove from heat.
In another saucepan, stir the corn and chicken stock together, bring to a boil and then simmer for 10 minutes. Then, pour the stock and corn into the other saucepan with the white sauce, whisking as you pour to prevent lumps. Add the cooked beans to the chowder. Return the entire mixture over the heat and bring to a boil and let it thicken as it boils. Slowly stir in the milk and let thicken. Season with salt and pepper to taste.
Serve White Bean & Corn Chowder with sliced green onions as garnish.