The sheet music and lyrics for namas te narasiṁhāya can be found here:
The music notation is arranged for keyboards & stringed instruments, in grand staff, as well as, the Vedic music system of Sa Re Ga Ma etc. Namas te narasiṁhāya also known as, Śrī Nṛsiṁha Praṇāma.
The mantra was written by Śrīla Vyāsadeva in Sanskrit, appearing in the Nṛsiṁha Purāṇa