What right did the English nobles gain from king John signing the Magna Carta

Magna Carta gave the English nobles a number of rights, most notably a protection from illegal imprisonment, access to justice and a fair trial and a limitation on the amount of feudal payments (an equivalent of today's taxes) that the noblemen owed to the king.

Some context: Magna Carta, is Latin for "The Great Charter" and was signed by Kind John of England in 1215. With this document, the King tried to appease rebel barons who were opposing his rule. With time, the exact influence of the Magna Carta changed, through actual changes in the text and through the way it was interpreted and implemented, but one legacy of the Magna Carta remained: this document established that even the king was limited in the things he was allowed to do, and that the king was not "above the law".