The chronicle is preserved on a single clay tablet found in 1882 and now kept at the British Museum. Like the other Babylonian Chronicles, it lists in an annalistic (year-by-year) fashion the key events of each year, such as the accession and deaths of kings, major military events and notable religious occurrences. The tablet itself is fairly large, measuring 140 mm wide by 140 mm long, but is significantly damaged with its bottom and most of the left-hand side missing. The text is fragmentary, consisting of some 300-400 lines of which only little more than 75 are still legible.
The text of the chronicle begins presumably with the accession of Nabonidus in 556 BC, though the start of the text is so poorly preserved that this is unclear. It mentions campaigns by Nabonidus against a place named Hume and unnamed localities in "the West" (Arabia?). Cyrus's pillaging of Ecbatana, the capital of Astyages, is recorded in the sixth year of the reign of Nabonidus. The chronicle goes on to describe in several entries the self-imposed exile of Nabonidus in the Arabian oasis of Tema and the disruption that this caused to the Akitu (New Year) festival for a period of ten years. The eighth year is purposefully left blank; apparently the scribe did not have any significant events to record for that year. Another campaign by Cyrus is recorded in the ninth year, possibly representing his attack on Lydia and capture of Sardis.
Much of the rest of the text is fragmentary. A possible reference to fighting and Persia appears in what is presumably the entry for the sixteenth year. A long surviving section describes the events of Nabonidus's seventeenth and final year as king, when Cyrus invaded and conquered Babylonia. The celebration of the Akitu festival is recorded, indicating Nabonidus's return to Babylon. The chronicle provides no information on why Cyrus chose to invade Babylonia at that time but records that the gods of various cities "entered Babylon", presumably referring to a gathering of cultic statues in advance of the Persian invasion. It provides a terse description of the Battle of Opis, in which the Persians decisively defeated Nabonidus's army. The Persian army went on to capture of the cities of Sippar and Babylon itself without further conflict. Cyrus is reported to have been received with joy by the city's inhabitants and appointed local governors, with the gods that had previously been brought to Babylon being returned to their homes. The legible portion of the text ends with a lengthy period of mourning for the lately deceased king's wife (presumably meaning the wife of Cyrus, as Nabonidus was no longer king by this time) and a mention of Cambyses, the son of Cyrus. Only a few scattered words are legible in the remainder of the tablet.
The Nabonidus Chronicle appears to have been composed by the (Babylonian) priests of Marduk, the chief god of Babylon. It has been characterised as "a piece of propaganda at Cyrus's service and as possibly "the result of the propaganda of the priesthood of Marduk to vilify Nabonidus". Julye Bidmead attributes the priests' hostility to Nabonidus's unsuccessful attempts to introduce the worship of the moon god Sîn. In particular, it repeatedly asserts that the Akitu festival could not be held because of Nabonidus's absence. This is dubious, as others could have participated in the celebration in Nabonidus's place. The chronicle is seen as part of a series of pro-Persian documents, including the Cyrus cylinder and Verse Account of Nabonidus, that attack Nabonidus for alleged religious infidelity and contrast his actions to those of Cyrus and Cambyses.