With no links to sources, and no census-specific information, I can't verify that this os the same person; but it appears to be the same person as the one shown here:
These early census records claim she is Black, but that doesn't mean she is. The census takers weren't very precise with race. They used a few labels (Black, mulatto, etc,) as a catchall label for "not white."
Still, when census takers got more precise in later censuses, some of her children still claim they are Black. So if Nicy wasn't Black, the children's other parent might have been.
Sources
Ancestry.com. 1850 United States Federal Census [database on-line]. Lehi, UT, USA: Ancestry.com Operations, Inc., 2009. Images reproduced by FamilySearch.
Ancestry.com. 1860 United States Federal Census [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2009. Images reproduced by FamilySearch.
Ancestry.com. 1870 United States Federal Census [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2009. Images reproduced by FamilySearch.