Nigel (c. 1100–1169) was an Anglo-Norman clergyman and administrator who served as Bishop of Ely from 1133 to 1169. He came from an ecclesiastical family; his uncle Roger of Salisbury was a bishop and government minister for King Henry I, and other relatives also held offices in the English Church and government. Nigel owed his advancement to his uncle, as did Nigel's probable brother Alexander, who like Nigel was advanced to episcopal status. Nigel was educated on the continent before becoming a royal administrator. He served as Treasurer of England under King Henry, before being appointed to the see, or bishopric, of Ely in 1133. His tenure was marked by conflicts with the monks of his cathedral chapter, who believed that Nigel kept income for himself that should properly have gone to them.

Following the accession in 1135 of Henry's successor, King Stephen, Nigel remained as treasurer only briefly before his family was ousted from political office by the new king. Nigel rebelled and deserted to Stephen's rival Matilda, but eventually reconciled with Stephen. Although he subsequently held some minor administrative posts, he never regained high office under Stephen. On the king's death in 1154, Nigel was returned to the treasurership by the new king, Henry II. Nigel's second tenure as treasurer saw him return the administration to the practices of Henry I. He withdrew from much of his public work after around 1164, following an attack of paralysis. He was succeeded as treasurer by his son, Richard fitzNeal, whom he had trained in the operations of the Exchequer, or Treasury of England. Most historians assess that Nigel's administrative abilities were excellent, and he is considered to have been more talented as an administrator than as a religious figure.

Nigel's date of birth is uncertain, but it is likely to have been some time around 1100. Historians occasionally refer to him as Nigel Poor or Nigel of Ely, but before his elevation to the episcopate he was commonly known as Nigel, the bishop's nephew, or Nigel, the treasurer. He was probably a Norman by ancestry although he was brought up in England, which in 1066 had been conquered by the Duke of Normandy, William the Conqueror. Following William's death in 1087 his realm was divided between two of his sons. His middle son, William Rufus, inherited the Kingdom of England, and the Duchy of Normandy passed to his eldest son, Robert Curthose. The youngest son, Henry, received a grant of money, which he used to purchase a lordship in Normandy. The brothers fought amongst themselves for the next twenty years; the initial conflict was between Rufus and Robert, but after Rufus' death in 1100 Henry, who succeeded Rufus as King of England, also became involved. Eventually, in 1106, Henry captured Robert, imprisoned him for life, and took control of Normandy.

Nigel's uncle Roger, Bishop of Salisbury, saw to Nigel's education at the school of Laon in France, where he probably studied mathematics under Anselm of Laon. It is likely that his father was Roger's brother Humphrey. Other students at Laon included William de Corbeil, later Archbishop of Canterbury, Robert de Bethune, who became Bishop of Hereford, Geoffrey le Breton, future Archbishop of Rouen, and other men subsequently to hold bishoprics in the Anglo-Norman dominions.

When he took vows as a cleric is unrecorded, but Nigel held a prebend, an ecclesiastical office in the cathedral, in the see of London before holding one of the offices of archdeacon in the diocese of Salisbury, although which archdeaconry he held is unclear. Most modern historians believe that Nigel was brother to Alexander of Lincoln, later Bishop of Lincoln, but this relationship is not specifically attested in the sources, which state merely that both were Roger's nephews. William of Malmesbury, a medieval chronicler, considered both Alexander and Nigel to be well educated and diligent. Nigel attended the consecration of Bernard as Bishop of St David's at Westminster in 1115, and may have returned to England from Laon by 1112. From the time of his return until around 1120 he served as a royal chaplain and attested a number of royal charters.

Nigel first became Treasurer in the reign of Henry I, and seems to have held that office from around 1126. He was already a receiver, or auditor and administrator, in the treasury of Normandy, and he served as treasurer for both realms, moving with the king and court between England and Normandy. The date of his appointment is unclear, as until he became a bishop, royal charters listed him as "nephew of the bishop" (Roger of Salisbury) rather than by any office he held. In 1131, though, he was listed in a papal letter as "Nigel, the treasurer", which securely establishes that he held the office at that date.

In 1133, Roger of Salisbury secured the bishopric of Ely for Nigel. Ely had been without a bishop since 1131; after the two-year vacancy, King Henry made the appointment because he was settling outstanding business before leaving England to return to Normandy. At this time Henry also appointed Geoffrey Rufus to Durham, and Æthelwold to the newly created Diocese of Carlisle. Nigel was consecrated on 1 October 1133 at Lambeth by William de Corbeil – who was by then Archbishop of Canterbury – possibly with the assistance of Roger of Salisbury. Nigel continued to hold the office of treasurer until 1136, when he was replaced by a relative, Adelelm, although the historian C. Warren Hollister placed his departure from the office in 1133 with his appointment to Ely. The Constitutio domus regis, or Establishment of the King's Household, may have been written by Nigel, or possibly for his use, and probably was composed around 1135.

Ely had until 1109 been an independent monastery, but its last abbot, Richard, had proposed to the king a plan by which the abbey would become a bishopric, presumably with the abbot himself as bishop. Richard died before the proposal could be put into operation, but in 1109, the custodian of the vacant abbey secured permission to make the change and became the first Bishop of Ely. However, the administrative changes needed to make the abbey into a bishopric took longer, and were still unresolved at the time of Nigel's appointment. Regardless, Nigel was constantly at court, as shown by his appearance 31 times as a witness to charters during the last ten years of Henry I's reign. This left little time for administration of his diocese, and Nigel appointed a married clergyman, Ranulf of Salisbury, to administer the diocese. Ranulf seems to have tyrannized the monks of the cathedral chapter, and Nigel appears to have done little to protect his monks from abuse.