In a large stockpot, combine the broth, potato, corn, garlic, marjoram, thyme, and pepper. Bring to a boil. Reduce the heat; cover and simmer until the potatoes are tender, about 15-20 minutes.
In a separate bowl, whisk the flour and milk until smooth. Gradually add to the vegetable and broth mixture.
Bring the chowder base to a boil, and stir until slightly thickened, about 2 minutes. Reduce the heat and stir in the cheese until melted.
Add the cooked, cubed chicken and continue to stir until everything is heated through. Remove from the heat and serve immediately.
Notes
Optional: I like to garnish mine with some fresh chives or chopped green onion. You could also add a dollop of sour cream or sprinkle on some more cheese. Yum!