If for some reason a person cannot light menorah, there is a takanah that he can recite the bracha of she'asah nisim when he sees someone else's menorah burning - birchas ha'roeh. B'pashtus, this bracha is a hoda'ah on the miracle of chanukah. Even if a person cannot do the actual mitzvah of lighting and recite the birchas hamitzvah on the hadlakah, he still can recite this birchas ha'shevach on the nes.
When we light menorah we recite this same bracha of she'asah nisim. Yesh lachkor: is this the same birchas ha'shevach on the nes that is recited by someone who cannot light, or does the fact that it is recited while lighting link it to the birchas ha'mitzvah on the hadlakah?
It could be that this issue hinges on a dispute between Rama and Mes Sofrim. Rama paskens that all the brachos -- l'hadlik ner, she'asah nisim, she'hechiyanu -- should be recited before the hadlaka. Mes Sofrim writes that only the bracha of l'hadlik ner is recited before the lighting; the other brachos are recited afterwards.
A birchas hamitzah always has to be recited over l'asiyasan, before the mitzvah. Since Rama requires that all the brachos ideally be said over l'asiyasan, it seems to indicate that all the brachos, including she'asah nisim, are linked to the mitzvah of hadlakah. According to Mes Sofrim, the bracha of she'asah nisim stands on it's own; whether you are not lighting and just seeing someone else's candles or whether you are lighting and seeing your own candles, it is the same birchas ha'shevach.
The Rishonim debate whether a traveler who has someone lighting for him at home, e.g. the person's wife, recites a birchas ha'roeh or not. If the bracha is purely a birchas ha'shevach, then the fact that someone else lit in the person's home should not impinge on their obligation to give hoda'ah for the nes. But if the she'asah nisim on lighting is like a birchas ha'mitzvah, then when the person's wife lit, she was already motzi him in the lighting and all the brachos.
So far so good. Now for the fly in the ointment:
R' Akiva Eiger (Shu"t, MhT #13) discusses whether someone who forgot to say the brachos on ner chanukah before lighting can do so afterwards. Lichorah, this should depend on the two sides of our chakirah. If she'asah nisim is treated like a birchas hamitzvah, then the opportunity was lost; if it is like the birchas ha'roeh and is shevach on the nes, then it can still be recited. Yet R' Akiva Eiger writes that even according to the view that holds that if a traveler's wife lights for him he is yotzei all the brachos, i.e. she'asah nisim in that context is like a birchas hamitzvah, he can still say the bracha after lighting if he forgot to do so beforehand. How do you get those two views to square together?