If you were speaking of the second nun's tale go to gradesaver's study guide for a full analysis-
The Prioress' Tale is overtly a “Miracle of the Virgin”, a reasonably common Christian genre of literature which represents a tale centered around Christian principles and a devotion to the Virgin Mary, but within the warm affection that the Prioress shows for her Christian faith is a disquieting anti-Semitism immediately obvious to the modern reader in our post-Holocaust times.
The tale is an unabashed celebration of motherhood, and an unapologetic argument for the virtue of Christianity over Judaism, and in most critics’ readings, it partly serves as a grim reminder that anti-Semitism by no means began with Hitler in the Second World War. The guiding figure of the tale is the Virgin Mary, addressed directly in its prologue, who serves both as the exemplar for Christian values and as the intervening spirit who sustains the murdered child before he passes on to heaven. Her mortal parallel is the mother of the murdered boy, who dearly loves her son and struggles to find the boy when he is lost.
The Tale itself, as Seth Lerer has pointed out is "a nightmare of performance..." which "dramatizes just what happens when a performer faces a hostile audience". The little clergeoun of the tale (the child) is an unsuspecting victim, murdered solely because of his eagerness to sing: one of many tales which seems to take as its theme the danger of speaking, the potential danger of words and language, and a warning about what happens to people who open their mouths at the wrong moment (other such tales include those of the Manciple and the Nun’s Priest).
Despite its interest in song and performance, the key question still seems to be whether we are to read the tale as an outdated example of anti-Semitism, acceptable to a medieval audience but acceptable no longer or whether there is another option. If there is, it probably lies in the sentimental presentation of the Prioress’ Tale, and the juxtaposition of the extremely angelic singing seven year old, and the extremely cruel and horrible Jews (who even go to the lengths of throwing the child’s corpse into a cesspit). If we remember that the Prioress is a woman so sentimental that she even cries over a dead mouse, it’s quite a contrast in her personality that she expends such vitriol over the Jews. Perhaps there is some sort of contrast; perhaps the Prioress is intended to be held at arm’s length from Chaucer. The bottom line with this tale is that it entirely depends on your reading of the details.