Demand is higher during the day. solar matches this better than the flat production of nuclear, so less storage per watt of production is needed for cheap solar energy when used to pump hydro storage, and even non pumped hydro can be varied to complement solar production and demand needs (within certain limits). And seasonally hydro and solar complement each other.

The land usage of pumped hydro isn't great, but since that's the same between both we'll ignore it for now.

Since the solar can be placed on top of the hydro dam water, or on the top of buildings, or used to shelter crops, the land use can and should be negative.

I very much doubt nuclear takes less material resources, but I don't have any good numbers for that off hand. Generally, cost is a reasonable proxy for energy and material input though (in the absence of large externalities) and solar costs less.

Again, hydro isn't super good for the environment, substiantially worse than nuclear and solar, but if you're going to build it to help nuclear deal with it's unhelpful power supply timing then you might as well use it for cheap solar.