Must one stand upon lighting the Chanukah candles?
One is required to stand when saying blessings which involve commands, such as when saying the blessing over Tzitzis, and Tefillin. Accordingly, one is required to stand upon saying the blessings over the Menorah lighting. However, technically, this only applies to the person reciting the blessing, and not to the bystanders, who may remain seated. Likewise, seemingly this only applies to the blessing itself, while the lighting may be done while sitting. Nonetheless, the widespread custom is to light while standing, and a Jewish custom is Torah. Therefore, initially the person saying the blessings and lighting the candles should do so in a standing position. Likewise, the widespread custom is for all the bystanders to stand for the blessing and lighting. Nonetheless, if it is difficult for one to stand then he may light it in a sitting position. Certainly, the listeners may sit in a time of need, such as due to weakness or exhaustion, or a pregnant and nursing mother and the like.
 Admur 8:3; M”A 8:2; Beis Yosef 8:1 in name Orchos Chaim Tzitzis 27 based on Yerushalmi “That which it states in the Yerushalmi that all blessings are to be said standing, it refers to Birchas Hamitzvos”; Haittur Zohar Tetzaveh brought in P”M 8 M”Z 1; P”M Pesicha to Hilchos Brachos 202:18 “We hold that Birchas Hamitzvos must be said standing” [however, see P”M 432 M”Z 3]; M”B 8:2 “All blessings of Mitzvos need to be done standing”
The reason: This is learned from Sefiras Haomer which is required to be said and blessed on in a standing position. [M”B ibid; See Kol Bo p. 16, brought in P”M 432 M”Z 3]
Cases of exception: The above rule is with exception for the blessings made over Shechitah and Challah, being that these two Mitzvos don’t hold the same weight as other commands, as they are done merely for the sake of being able to eat food. [Admur ibid; M”A 8:2] Vetzaruch Iyun according to this ruling here why we are accustomed today to sit by various blessings of Mitzvos, such as “Al Achilas Matzah”; “Leishev Basukkah” and others. See P”M Pesicha to Hilchos Brachos 202:18 who explains that since these Mitzvos involve eating, they may be said in a sitting position; See Bach 8; Pnei Yehoshua Megillah 21a; Mor Uketzia 8; Piskeiy Teshuvos 8:4 who differentiate between Mitzvos that are performed standing versus sitting.
Other opinions: Some Poskim rule that the blessings of Mitzvos are not required to be said in a standing position, with exception to those Mitzvos that must be performed standing. [P”M 432 M”Z 3 “Chazal instituted the blessing similar to the performance if it is done standing”; Artzos Hachaim 8:1 states it is only a Mitzvah Min Hamuvchar; Bach 8 only requires standing for Mitzvos that have no benefit; See Pnei Yehoshua Megillah 21a; Mor Uketzia 8 that depends it if the Mitzvah is accustomed to be performed standing; Piskeiy Teshuvos 8:4]
 Birur Chaim 2:1 [pp. 198-203]; See regarding Shofar: Admur 585:2; Ben Ish Chaiy Netzavim 15 brought in kaf Hachaim 585:1; See also Yifei Laleiv 2:2; Kaf Hachaim 690:2 that so was custom of the Beis Keil shul in Jerusalem; Mikraeiy Kodesh brought in Piskeiy Teshuvos 690:1; Stringent opinion by Shofar [not relevant to Chanukah as we don’t apply Shomeia Keoneh]: Kaf Hachaim 585:1; Machatzis Hashekel on M”A 690:1 regarding Megillah; Beis Oved 690:9 brought in Kaf Hachaim 690:2; Shaar HaTziyon 690:1
Other opinions: Some Poskim rule that one is required to stand also for the actual lighting. [Chakal Yitzchak 3; However, see Birur Chaim who negates his proofs, and so seems clearly evident from all the sources that one is not required to stand]
 Setimas Kol Haposkim who omit writing of any obligation or necessity to stand during the lighting which proves that the sages never established that it be done in a standing position. Now, although the blessing must be recited in the standing position this does not certainly mean that the lighting which is the mitzvah must be done in the standing position, as these are two separate matters as proven from the two Halachos in Admur 8:3-4 which distinguishes between the obligation to stand for the blessing over Tzitzis versus the obligation to stand while putting it on while putting it on and so is also proven from the reading of the Megillah which may be read sitting when reading it in private even though one must stand for the blessings. [See Michaber 690:1]
 See Rameh 102 that there are number of Mitzvos which were accustomed to be done standing; Chakal Yitzchak 3 that so is the custom to both say the blessing and light it while standing and that so was done in the Temple lighting; Nitei Gavriel 27:2 footnote 2; See Birur Chaim ibid