Butter a 9 x 13 x 2-inch baking pan. In a large bowl, add chocolate chips, marshmallow cream, vanilla, Bailey's Irish Cream and nuts. Set aside. Heat butter, sugar and milk to a boil, reduce heat and cook slowly for 11 minutes, stirring constantly. Pour milk mixture over the ingredients in bowl and stir slowly, by hand, to blend. Pour fudge into prepared pan and chill. When fudge is set, cut into 1-inch pieces. Yields 117 squares.