Place potatoes in a large saucepan; cover with water. Bring to a boil over medium-high heat. Reduce heat, and simmer 15 minutes or until tender; drain.
Combine whole milk and butter in a small saucepan, and cook over medium-high heat until butter melts. Remove milk mixture from heat.
Return potatoes to pan; mash with a potato masher to desired consistency. Add milk mixture, salt, and pepper, stirring until well combined. Stir in chopped fresh chives.