Honestly don't do anything... Scandinavian winter here too, but not that cold as Sweden, however -12C we have peaked this year.
Coating on lens is fine, it won't hurt the front element, and NIKON D3xxx D5xxx D7xxx and Dxxx DX series are plenty weather sealed for the condensation to be on the outside of the gear, you won't get any issues internally..
Worth to notice is that condensation will appear when something is colder then ambient temperature, as in when you bring it back inside, but the condensation will appear where the heat (indoor ambient in this case) surrounds the cold... Thereby it will be slightly moist/wet on the outside, inside will be just fine.
If you worry about the outside of your gear, what you can do will be to wrap it in kitchen plastic foil/wrap, that will make the water appear on the outside of the plastic
I've used this method on electronics cooled at -196C.