Preheat oven to 325 degrees.
In baking pan, place 1 cup water and chicken, liberally seasoned with salt, pepper, and butter. Bake, covered, until tender. Skin and bone chicken, reserving broth. Wash and cut vegetables into bite-sized pieces. Remove corn from cob; add garlic and onion. Cut jalapeños into half-inch squares. Place cooked chicken, broth, and vegetables in large saucepan. Add beer or 1½ cups water. Cover and simmer 15 to 20 minutes over low to medium heat. Do not let ingredients stick to bottom of pan. Mix butter with flour and add just enough to thicken mixture.
Serve in bowls with flour tortillas.