The normal way that JewishGen represents Ukrainian birth records is like this:
where in the second column, the top box contains the father's name (Ber) above the father's father's name (Perel). So the father of Froim is Ber son of Perel.
Similarly the middle box contain the mother's name (Blyuma) above the mother's father's name (Meer). So the mother of Froim is Blyuma daughter of Meer.
When there are different alternatives for a name, they are kept on the same line separated by slashes "/", e.g.:
So in this case, the father could be Elya, Ella, or Eliahu. The mother can be Yuta, Ita, or Yetta.
Notice the grandfather lines have a dash "-" meaning the grandfather's name was not given on the birth record.
So in your case, Zalman and Nokhim Nakhum are two alternatives for the father's name, and Zlata or Zlota are two alternatives for the mother's name.
Similarly for you, the grandparents (father's father and mother's father) are both given as the same two alternatives of Girsh or Hirsh.
Now you say:
Our family records indicate different information, that Tzippa's parents were Abraham Chaim Kinsbursky (son of Nochim Kinsbursky) and Sheyne Leah Stolberg (daughter of Zalman Stolberg).
Whereas this record is for Tsipah, daughter of Nokhim. Is it possible that this Tsipah was your Tzippa's aunt? Maybe she died and your Tzippa was named after her, as is the custom. Does the birth year 1882 correspond to when your Tzippa was born, or was it a few years earlier?
With regards to surnames, they are listed in the first column containing the Name column for the individual. The Father, Mother and Grandfather fields do not include surnames. The only other surname that might be listed is the mother's and that would be in the bottom box in the second column, like "Zingman" in this example:
It is likely quite rare that both grandparents would have the same name. And in fact, looking at other listings in that database, most are different, but a few are not, e.g.:
What's interesting is that I can find records with no grandparents listed, and records with both grandparents listed, but there are none with just one grandparent listed.
My suspicion is that whatever program they used to load this database duplicated the grandparent's name when the other wasn't listed.
So I would say then in your case, that one of the grandparents of Tsipah was Girsh/Hirsh and the other wasn't specified.
The only real way to know for sure would be for you to try obtain a copy of the original record and get a translation of it. If you would like to do so, then go the the JewishGen Ukraine SIG page for the town involved (in your case Niezhin): https://www.jewishgen.org/Ukraine/GEO_town.asp?id=359
The records may be available from the "Document and Dataset Collections" section on that page. If not, then contact the Town Leader who is listed on the page to find out how you might be able to obtain a copy of the original.
Obtaining records for your family is the best way to piece together your Ukrainian Jewish roots. If you find one record for a family member, you will often find several. So it is very worthwhile to try to find someone who is an expert with that particular record set to help you.