the alvars were vaishnavites (devotees of vishnu) while the nayanars were shaivites (devotees of shiva)

No. there can't be. Nayanars are collectively called worshippers who pray and save for Lord Shiva. There were 63 nayanars as per the Tamil Literature and they worshipped and served for Lord Shiva.

alwars are saints of maha vishnu and nayanars ars saints praised lord sivan

Alvars were Tamil poet-saints who worshipped Lord Vishnu, while Nayanars were Tamil poet-saints who worshipped Lord Shiva. Both groups played significant roles in the Bhakti movement in South India during the medieval period.

Appar Swamigal is commonly referred to as Thirunavukkarasar or Navukkarasar. He was a 7th-century Tamil Shaivite saint and poet who composed devotional hymns in praise of Lord Shiva. He is one of the 63 Nayanars, the revered saints of the Shaivite tradition in South India.