Shulchan Arukh Orach Chayim · Siman 682

English

All eight days of Chanukah one says "For the Miracles" in the grace after meals in the blessing of the land, and in prayer during the blessing of thanksgiving. If one did not say it, one does not return [in order to repeat and make the proper insertion]. (See above chapter 294 paragraph 4 and 5) . However, if one remembered while still saying the blessing, as long as one has not said the name of God [in the closing line of the blessing], even if one remembered between the words "You" and "God", one should return [and make the proper insertion]. Rema: There are opinions that if one forget "For the miracles" in the grace after meals, when one reaches "the merciful one", say: "May the merciful one make miracles for us just like You make for our forefathers in those days at this time, in the days of Matityahu etc."[Kol Bo] [and this was explained in chapter 187 paragraph 4]

English

Also in the musaf prayer on shabbat and Rosh Chodesh one must mention Chanukah, even though there is no musaf prayer on Chanukah.

English

It is not said [as part of the text of "Al HaNisim"]: "Keshem Sheasita, etc" [Just as you did with our ancestors...] but ends the prayer by saying: "VeAsita Imahem Nisim Ugevurot, Bayamim Hahem, Baet Hazot" [ you did miracles and wonders with them, in those days, on these dates]. In any case, there are those who culminate as the formula raised above.