Starting nukes with the hope of power in ten or fifteen years will not help keep anybody warm in the meantime.
Transmission lines ought to be quite a lot quicker to complete.
Yes, the north is oversupplied, because they have most of the hydro. Remember though that hydro is a form of storage, so even if the transmission capacity was higher, it'd deplete faster. I don't have the numbers off the top of my head, but I highly doubt that transmission alone can solve the issue long term, even less so the short term ones. Again, dispatchable and/or baseload energy is a MUST. And the people who yesterday sold solar dreams are today selling energy storage dreams. It's the same great story, but it doesn't exist. Nuclear exists, and it's carbon neutral. It's better to start now, then to not start at all or resorting to oil/gas.
There is one good short-medium term effect of the government change, for nuclear. Maintaining and/or restoring the existing reactors could be done much faster than building new ones. Not all reactors in Sweden are operational today.
https://www.nyteknik.se/energi/svenska-kraftnat-miljardinves...