Matsya Purana — Catalogue of the Eighteen Puranas
नन्दाया यत्र माहात्म्यं कार्त्तिकेयेन वर्ण्यते नन्दीपुराणं तल्लोकैर् आख्यातमिति कीर्त्यते //
nandāyā yatra māhātmyaṃ kārttikeyena varṇyate nandīpurāṇaṃ tallokair ākhyātamiti kīrtyate //
That text in which the greatness of Nandā is described by Kārttikeya is celebrated among people as the “Nandī Purāṇa”; thus it is proclaimed.
This verse does not discuss pralaya; it identifies a Purāṇa by its subject matter—Nandā’s māhātmya as taught by Kārttikeya.
Indirectly, it guides kings/householders toward authoritative sources: it classifies sacred literature so a listener can seek the correct Purāṇa for a desired māhātmya (devotional and dharmic instruction).
No Vāstu or temple-building rule is stated; the ritual takeaway is bibliographic—this is a naming/identification marker for a text centered on Nandā’s sacred glory and Skanda’s instruction.