The narrations in Tanwir al Miqbas min Tafsir ibn ‘Abbas vary in their level of authenticity, depending upon the reliability of the narrators themselves. Chains from Mu‘awiyah ibn Salih and Qays ibn Muslim al Kufi are considered Sahih and those from Ibn Ishaq are considered Hasan; whilst those from Isma‘il ibn ‘Abdur Rahman as-Suddi al-Kabir and ‘Abdul Malik ibn Jurayj are doubtful. Those from ad-Dahhak ibn Mazahim al Hilali, ‘Atiyah al-‘Awfi, Muqatil ibn Sulayman al-Azdi, and Muhammad ibn as-Sa’ib al-Kalabi, who was accused of fabricating ahadith, are all da‘eef. Nearly all of the Tafsir is based on statements narrated in chains containing Muhammad ibn as-Sa’ib al-Kalabi. Hence, this Tafsir is considered unreliable for the most part; and, despite its popularity amongst the masses, it is totally rejected by Muslim scholars.
[Mabahith fi ‘Uloom al-Qur’an Pp. 360-62 and at-Tafsir wa al-Mufassirun Pp. 81-3]