1.One who forgets to recite al ha-nissimin Birkas Hamazon — although he does not return to that point — nevertheless, when he reaches Harachaman he should add the following: “May the Merciful perform for us miracles and wonders as You performed for our ancestors in those days at this time: In the days of Matisyahu, son of Yochanan…” etc. Similarly, if one forgot to recite al ha-nissim in Shemoneh Esrei, he should say that formula (“May the Merciful” etc.) at the conclusion of Shemoneh Esrei, before the words “Yihiyu l’ratzon,” as a supplication (Shulchan Aruch and Mishnah Berura, section 670)
2. When the Three-Faceted-Blessing (“Al Ha-michya” etc.) is recited on Chanukah, al ha-nissim is not mentioned at all. This is because the Rabbis enacted it to be said within a blessing of praise, and there is no clause of “Nodeh Lecha” in the Three-Faceted-Blessing. (ibid. and Eliyahu Rabbah)
