In a large saucepan, combine the broth, potato, corn, garlic, marjoram, thyme and pepper. Bring to a boil. Reduce heat; cover and simmer until potatoes are tender, 15-20 minutes.
Combine flour and milk until smooth; gradually add to vegetable mixture. Bring to a boil; cook and stir until slightly thickened, about 2 minutes. Reduce heat; stir in cheese until melted. Add the chicken; heat through.