General Notes

Title: International Standard Bible Encyclopedia
Publication: <http://www.searchgodsword.org/enc/isb/>
Note:
NAHASH
na'-hash (nachash, "serpent"; Naas):
(2) A king of Ammon, who, at the very beginning of Saul's reign, attacked Jabesh-gilead so successfully, that the inhabitants sued for peace at almost any cost, for they were willing to pay tribute and serve the Ammonites (1 Samuel 11:1). The harsh king, not satisfied with tribute and slavery, demanded in addition that the right eye of every man should be put out, as "a reproach upon Israel." They were given seven days to comply with these cruel terms. Before the expiration of this time, Saul, the newly anointed king, appeared on the scene with an army which utterly routed the Ammonites (1 Samuel 11:1), and, according to Josephus, killed King Nahash (Ant., VI, v, 3).

If the Nahash of 2 Samuel 10:2 be the same as the king mentioned in 1 Samuel 11, this statement of Josephus cannot be true, for he lived till the early part of David's reign, 40 or more years later. It is, of course, possible that Nahash, the father of Hanun, was a son or grandson of the king defeated at Jabesh-gilead by Saul. There is but little agreement among commentators in regard to this matter. Some writers go so far as to claim that "all passages in which this name (Nahash) is found refer to the same individual."

(3) A resident of Rabbath-ammon, the capital of Ammon (2 Samuel 17:27). Perhaps the same as Nahash (2), which see. His son Shobi, with other trans-Jordanic chieftains, welcomed David at Mahanaim with sympathy and substantial gifts when the old king was fleeing before his rebel son Absalom. Some believe that Shobi was a brother of Hanun, king of Ammon (2 Samuel 10:1).
Title: Nave's Topical Bible
Publication: http://www.studylight.org/con/ntb/
Note:
NAHASH
An Ammonite king
1. Defeated by Saul at Jabesh-gilead -- 1 Samuel 11:1-11 (Kindness of, to David, and death -- 2 Samuel 10:1,2; 1 Chronicles 19:1,2)
2. Probably identical with JESSE -- 2 Samuel 17:25
Title: Easton's Bible Dictionary
Publication: <http://www.studylight.org/dic/ebd/>
Note:
NAHASH
Serpent.
1. King of the Ammonites in the time of Saul. The inhabitants of Jabesh-Gilead having been exposed to great danger from Nahash, sent messengers to Gibeah to inform Saul of their extremity. He promptly responded to the call, and gathering together an army he marched against Nahash. "And it came to pass that they which remained were scattered, so that two of them [the Ammonites] were not left together" (1 Samuel 11:1-11).

2. Another king of the Ammonites of the same name is mentioned, who showed kindness to David during his wanderings (2 Samuel 10:2). On his death David sent an embassy of sympathy to Hanun, his son and successor, at Rabbah Ammon, his capital. The grievous insult which was put upon these ambassadors led to a war against the Ammonites, who, with their allies the Syrians, were completely routed in a battle fought at "the entering in of the gate," probably of Medeba (2 Samuel 10:6-14). Again Hadarezer rallied the Syrian host, which was totally destroyed by the Israelite army under Joab in a decisive battle fought at Helam (2 Samuel 10:17), near to Hamath (1 Chronicles 18:3). "So the Syrians feared to help the children of Ammon any more" (2 Samuel 10:19).
Title: Smith's Bible Dictionary
Publication: http://www.studylight.org/dic/sbd/
Note:
NAHASH
(serpent).
1. King of the Ammonites who dictated to the inhabitants of Jabesh-gilead that cruel alternative of the loss of their right eyes or slavery which roused the swift wrath of Saul, and caused the destruction of the Ammonite force. (1 Samuel 11:2-11) (B.C. 1092.) "Nahaph" would seem to have been the title of the king of the Ammonites rather than the name of an individual. Nahash the father of Hanun had rendered David some special and valuable service, which David was anxious for an opportunity of requiting. (2 Samuel 10:2)
Title: Old Testament Hebrew Lexicon
Publication: http://www.studylight.org/lex/heb/
Note:
NAHASH
Nahash = "serpent" n pr m (naw-khawsh')
1. a king of the Ammonites during the time of king Saul

SOURCES:
1 Samuel 11:1
Wikipedia