Yes, you can boil milk in a kettle, but it is important to keep a close eye on it to avoid boiling over or scorching the milk. It is recommended to use a kettle with a temperature control feature and to stir the milk occasionally while heating it. It is also important to clean the kettle thoroughly after boiling milk, as it can leave behind residue that can affect the taste or quality of other beverages or foods cooked in the kettle.