It took 6 years to defeat the bad guys during the second world war.
Most of the guys that defeated them had little to no military training at the onset of the conflict.
The NIMBYs in that scenario were marketed to with either assured oppression, or war with a "better" future. Same can be done today.
You can't just throw all democracy laws and regulations overboard just because Russia is messing in their backyard (okay - that is an understatement, but you get the point)...
In the slightly longer term, the rest of the world really needs to get off of fossil fuels and be cutting carbon and other greenhouse gas emissions. This is critical and urgent, but not at the cost of the rule of law or democracy.
We can't throw all democracy laws and regulations overboard, but we can't continue with statue quo. Without energy we don't have working cities, agriculture stops producing food, heating and then public health starts to break down. The agricultural sector was one of the first areas that got hit when energy prices jumped.
Those things are close enough to be wartime-like, and could easily turn into actually wartime.
For example, in both WW1 and WW2 a lot of capital ship constructions were canceled in favor of cheap quick to built ships (like cheap destroyers or submarines).
The liberty ships are another example, these things were kind of obsolete at launch and not really geared toward lasting that long (5 years engineered life span).
Lastly, we are not exactly in a wartime situation. Some emergency decisions need to be made (temporary LNG terminals for example), and also Europe needs to have an hard look at its energy policies, but that's a long term and for more complex set of decisions.
A long term commitment to nuclear energy is not something that could and even should be taken in the heat of the moment.
It takes 5-7 years to build a nuclear plant? That means the best time to build them was more than 5-7 years ago. The second best time is right now.
This is no heat of the moment decision. We've had nuclear power technology for 75 years and know how to use it by now.
Well, kind of, whatever the outcome, Russia will have depleted much of its military strength and will need to reequip its army. That costs money, so they will be more or less forced (or even willing in case of a coup against Putin) to sell gas to the EU.
The real question is more what the EU will do. Most likely, the EU (or each country individually) will really want to diversify their energy sources and maybe be more self-reliant to not be subject to one actor like it is right now.
Nuclear may be one of the responses, but it's far from the only one.
On a side note, Russia is providing ~25% of the EU's uranium right now (in fairness, this dependency is easier to circumvent compared to the gas one).