There are six different types of Tithi in Hindu astrology. Nanda Tithi is one among them. Pratipada, Sashti and Ekadasi are Nanda tithis. They are considered generally good tithis.
The tithis are good for all auspicious events.
Activities done during the Nanda Tithi period will bring peace and prosperity.
Food donation and helping people during the period will help in redemption.