For hard numbers, see real-world case studies like Denmark:
https://en.wikipedia.org/wiki/Renewable_energy_in_Denmark
They get 50% of their electricity from just wind. So that's the lower bound on what you can achieve in the real world today. Here's how you increase that without needing any storage technology:
(1) Be a very large land mass like the United States, where wind variability is more likely to cancel out.
(2) Add solar instead of only relying on wind. Solar cancels out wind variability because it's more windy when it isn't sunny.
(3) Overbuild by 2-3x, so that the troughs in energy aren't so bad. Even if you overbuild by this much, it's still a lot cheaper and faster to build out than nuclear.
(4) Import solar/wind from neighboring countries, losing only 10-15% due to resistivity.
I don't know exactly what % renewables you can achieve by picking all this low hanging fruit while still being cheaper than Nuclear. 80%? 99%? If you add solar and you overbuild and you have access to a large landmass like the US, you can probably get very, very high, with the last few % being powered by natural gas peaker plants as a temporary stop-gap until storage technology becomes good enough.
As a bonus, if you overbuild, you can sell surplus energy to Mexico and make money!