To a large Dutch oven or stockpot, add the oil and heat over medium-high heat to warm.

Add the onion, carrots, celery, and sauté for about 7 to 9 minutes, or until vegetables begin to soften. Stir intermittently.

Add the garlic and sauté for another 1 to 2 minutes.

Add the flour and whisk constantly until lightly browned, about 1 minute.

Add the chicken broth, milk, and whisk constantly until slightly thickened, about 1 to 2 minutes.

Add potatoes, thyme, oregano, salt, pepper, optional cayenne, and bring to a boil. Allow chowder to boil fairly rapidly for about 15 minutes or until potatoes are fork-tender; stir intermittently. At any time while the chowder is boiling, if the overall liquid level is lower than you like and the chowder is too thick, adding a cup of extra milk is okay. At the end you will adjust the seasoning levels.

After potatoes are soft, add the chicken, corn, and boil for 1 to 2 minutes to warm the chicken and corn through.

Reduce the heat to low, add the cheese slowly, and stir continuously until melted and combined.

Add the parsley and stir to combine.

Taste chowder and add salt to taste. I added another teaspoon but this will vary based on how salty the brand of chicken broth used is, how salty the rotisserie chicken and cheese are, and personal preference. Make any necessary seasoning adjustments (i.e. more salt, pepper, herbs, etc.) and serve immediately.