But Nadab the son of Jeroboam reigned over Israel the second year of Asa king of Juda: and he reigned over Israel two years.

And Nadab son of Jeroboam hath reigned over Israel, in the second year of Asa king of Judah, and he reigneth over Israel two years,

Nadab, the son of Jeroboam, became king over Israel in the second year that Asa was king of Judah; and he was king of Israel for two years.

Yet truly, Nadab, the son of Jeroboam, reigned over Israel, in the second year of Asa, the king of Judah. And he reigned over Israel for two years.

The sacred historian now gives an account of the contemporary kings of Israel, beginning with Nadab, who ascended the throne in Asa's second year, and concluding with Ahab, in whose fourth year Asa died. This narrative occupies him almost to the close of the first Book of Kings.
Chronology of Kingdoms Year of the Divided Kingdom Kings of Judah Years of Reign Kings of Israel Years of Reign 1 Rehoboam 17 Jeroboam 22 5 (Invasion of Shishak) 18 Abijam 3 20 Asa 41 22 Nadab 2 23 Baasha 21 31 (Invasion of Zerah) 34 (Great Feast at Jerusalem) 46 Elah 2 47 Zimri
Omri 12 58 Ahab 22 61 (Last year of Asa) (4th year of Ahab)

Nadab - began to reign over Israel - He began his reign in the second year of the reign of Asa, and reigned two years.

And Nadab the son of Jeroboam began to reign over Israel in the second year of Asa king of Judah,.... Before Baasha did:
and reigned over Israel two years, not two whole years; for he began in the second of Asa, and in the third of that king's reign Baasha slew him, and reigned in his stead, 1-Kings 15:28.

During the single reign of Asa in Judah, the government of Israel was in six or seven different hands. Observe the ruin of the family of Jeroboam; no word of God shall fall to the ground. Divine threatenings are not designed merely to terrify. Ungodly men execute the just judgments of God upon each other. But in the midst of dreadful sins and this apparent confusion, the Lord carries on his own plan: when it is fully completed, the glorious justice, wisdom, truth, and mercy therein displayed, shall be admired and adored through all the ages of eternity.

NADAB'S WICKED REIGN. (1-Kings 15:25-34)
Nadab the son of Jeroboam began to reign--No record is given of him, except his close adherence to the bad policy of his father.

The Reign of Nadab lasted not quite two years, as he ascended the throne in the second year of Asa, and was slain in his third year.

Two years - Not compleat, as appears from 1-Kings 15:28 , 1-Kings 15:33.