Nicolaidou made her debut at the Opera National de Paris as Prima Sorella in Suor Angelica and returned for Kathe in Fenelon's Faust, Barbarina Le Nozze di Figaro alongside Erwin Schrott and Isabel Leonard, Amor in Orpheus und Eurydike, Soprano solo in Mahler's 4th Symphony. She has performed: Susanna in Le Nozze di Figaro (Festival Operklosterneuburg), Serpetta in La Finta Giardiniera (Bobigny MC93), Euridice in Orfeo ed Euridice (Theater Aachen), Flower Girl in Parsifal (Theater Aachen), Night and Fairy in The Fairy Queen (Theatre du Jorat), Mae Jones in Street Scene (Amphitheatre Bastille), Popelka in Martinu's Veselohra na moste (Festival Retz), The Mother in Menotti's Amahl and the Night Visitors (Cyprus), Peri's Euridice (Kammeroper Wien), Micaëla in Carmen (Vienna), Amore and Valetto in L'incoronazione di Poppea (Festival de Menton, France), Amor in Orpheus und Eurydike (David Koch Theater in Lincoln Center New York City) that marked her US debut. She has worked with conductors such as: Jun Merkl, Antoni Ros Marba, Philippe Jordan, Bernhardt Kontarsky, Thomas Hengelbrock, Jean- Christophe Spinosi, Dan Ettinger, Evelino Pido, Alkis Baltas, Markus Bosch, Dmitry Sitkovetsky.