In a large bowl, combine butter with peanut butter, powdered sugar, and vanilla extract until smooth. Fold in mini marshmallow bits. Roll the dough into balls, and set onto a plate. Refrigerate for at least 20 minutes.
Place the chocolate chips into a microwave safe bowl, and heat in the microwave in 30-second intervals, stirring well until it is fully melted and smooth.
Fully coat each peanut butter ball into the melted chocolate, and set onto plates. Refrigerate until the chocolate has completely set.
