The prediction of Maitreya being the next Buddha is universally accepted, taught, and believed by all Buddhist. There are some exceptions though with some Nichiren groups claiming that Nichiren is the True Buddha and it ends with him. For a Nichiren group to claim that Nichiren is the True Buddha and deny the prediction of Maitreya is a betrayal of what Nichiren believed and what is actually stated in the Lotus Sutra. This is a very important point and needs to be considered carefully. Either you follow Nichiren and his belief in the Lotus Sutra and thereby inherit Nichiren’s mission, or you don’t in which case it isn’t possible to claim to be a disciple of Nichiren and the Lotus Sutra. It defies logic by trying to work it both ways.