Chapter 11 (Ch 88 in the book)
With both Shumbha and Nishumbha dead, the gods, lead by Indra and Agni, praised the goddess. This is known as Narayani-stuti. Specifically, 18 shlokas in this chapter are referred to as the Narayani-stotram.
Saluting her as Vishweshvari, Ishvari, Vaishnavi, the gods praised her as the mother of all gods, as one who removed all ills, who could not be conquered in valour, who should be praised, but for whom words were insufficient to praise.
Addressing her as Narayani, the gods prostrated themselves before her, chanting that she existed in the form of kala, kashtha, and other portions of time, whose power led to the destruction of the universe, whose eternal power was behind the creation, preservation, and destruction of the universe, who was full of gunas, and so on. They praised her qualities in her different forms, like Narayani, Gouri, Brahmani, Vaishnavi, Maheshvari, Koumari, Varahi, Narasimhi, Aindri, Shivaduti, Lakshmi, Lajja, Vidya, Shraddha, Pushti, Svadha, Dhruva, Maharatri, Mahamaya, Saraswati, Babhravi (who grants boons of victory), Durga, Katyayani, Bhadrakali, Chandika, Ambika, they prayed to her to protect them from all sin. She was the refuge for men who never suffered, and who in turn became the refuge for others, and asked the goddess to confer a boon.
The goddess obliged and asked the gods to ask for a boon. The gods wanted the goddess to vanquish their enemies.
Devi then said that when the twenty-eighth yuga (dvapara) of the Vaivasvata manvantara arrived, there would be two other great asuras - Shumbha and Nishumbha - would be born. She would be born through Yashoda's womb and kill them. She would also destroy the danavs in Viprachitti's lineage, and in that form would be known as Rakdadantika.After a drought of a hundred years, she would appear in a form that would be known as Shatakshi (since should glance upon the sages with a hundred eyes) and sustain the world with vegetables. In that form, she would be known as Shakambhari. She would slay an asura named Durgama, and come to be known as Durga. She would also be known as Bhima. To slay a rakshasa named Arunaksha, she would assume the form of bees, and would be known as Bhramari.
In summary, she assured the gods that whenever danavas caused trouble, she would arise to vanquish them.
Reference: Markandeya Purana, translated by Bibek Debroy. Published by Penguin, 2019. The Devi Mahatmya is covered in chapters 78-90 of the Markandeya Purana.