If you're sure the LNAB for Kirsten was Unknown than we first need to correct the LNAB (into Unknown) and after that merge them. But before merging, correcting or changing names... is her LNAB Unknown for sure ?
I mean do you have searched for more sources and they all say the say the same ? So it was Unknown ?
Otherwise maybe you could try search for some sources or ask in G2G if someone maybe has a source where maybe more is known about her family ?
Now the NN profile only says she was known only as Kirsten Niels wife , but some genealogies also say she was named Christensdatter, so I really think we need more sources to make sure what's best ?