Nadab (meaning liberal, generous) was the name of several individuals in the Old Testament of the Bible:

1. The eldest of Aaron's four sons (Exodus 6:23; Numbers 3:2). He, with his brothers and their father, was consecrated as a priest of Jehovah (Ex. 28:1). He afterwards perished with Abihu for the sin of offering strange fire on the altar of burnt-offering (Leviticus 10:1, 2; Num. 3:4; 26:60).
2. Nadab of Israel king of the northern Kingdom of Israel, was the son and successor of Jeroboam, the king of Israel (1 Kings 14:20).
3. One of the sons of Shammai in the tribe of Judah (1 Chronicles 2:28, 30).

References

Tanakh people | Torah people

Nadab (Priester) | נדב ואביהוא