Place potatoes in a large pot and cover with water. Bring to a boil and generously salt water. Simmer until potatoes are tender, about 20 minutes. Drain well. Mash potatoes together with cream cheese, sour cream, chives, salt, and pepper. Beat with an electric mixer until smooth. Place in a storage container with the lid off and chill in refrigerator. When potatoes are cold, cover tightly with a lid.