Per Orach Chaim 693:2 if one forgot Al Hanisim by Davening there is no need to repray. What if I said Al Hanisim, however I said the Chanuka version on Purim - do I have to Daven again or not? (sources)
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The Rivevos Ephraim 1:457 brings the tzaddim of both sides,he ends off that one does not go back. Rav Shmuel Kamentsky in Kovetz Halachos 7:5 holds one is yotzei and doesn't go back.The tzad that says that chanukka has a little bit of the same inyun since it is a praise for a nes.