For the purposes of this question, assume Russia's Multipurpose Laboratory Module (MLM/Nauka) gets launched and makes it to the ISS.
Most articles I read say the MLM will dock at the FGB's nadir port (for example, the confusingly written Wikipedia page) At first writing of this question, I thought the DC-1 had been discarded as planned. No, it hasn't. I find the whole situation very difficult to sort out.)
AFAIK the Mini-Research Module 1 (MRM-1/Rassvet) is currently docked at the FGB nadir port. This NASA rendering from August 2019 shows it there (green arrow added by me).
What is the plan for MRM assuming the MLM is to replace it at the FGB nadir port?