These readings are identical in meaning: the first is based on verb form IV, with a second nūn read onto the same skeletal form. The second reading may be a version of the same word, or shortened from form II nunajjī. A third possibility is that it is from the passive perfect (nujjiya al-najāʾu al-muʾminīn) [al-Mahdawi].
He has revealed to you ˹O Prophet˺ the Book in truth, confirming what came before it, as He revealed the Torah and the Gospel
Explanation
These readings are identical in meaning: the first is based on verb form IV, with a second nūn read onto the same skeletal form. The second reading may be a version of the same word, or shortened from form II nunajjī. A third possibility is that it is from the passive perfect (nujjiya al-najāʾu al-muʾminīn) [al-Mahdawi].