Solar seems like a decent pair with nuclear. Use nuclear at the level of night-time load, solar covers the extra daytime demand, and any remaining discrepancy you cover with either storage or extra nuclear, whichever is cheaper.
A couple years ago MIT had a simulator online that let you try out different grid energy combinations to see their total cost, and this was the cheapest I came up with.
The one I mentioned let you pick different proportions of energy sources for the entire U.S. grid, and told you how much it would cost, the carbon impact, etc.
A couple years ago MIT had a simulator online that let you try out different grid energy combinations to see their total cost, and this was the cheapest I came up with.