1. All eight days of Chanukkah the additional paragraph “al ha-nissim” (“For the miracles”) is inserted in Birkas Hamazon(Grace after meals) and ShemonehEsrei. If one omitted saying it altogether, he does not go back [to correct the omission]. But if one remembered before uttering the Name of Hashem at the conclusion of the blessing [even if he had already said “Blessed are You”], he does return [to the point where al ha-nissim should have been said]. (Shulchan Aruch and Mishnah Berura, section 670)
2. Since al ha-nissim is a praise, not a request, it is inserted in the blessing of Modim (“We thank”) inShemonehEsrei and in the blessing of Nodeh Lecha (“We shall thank You”) in Birkas Hamazon. (ibid.)
