I can't see where wire nuts would be of use on batter terminals, but anyway. Over the years I've tried about every "battery terminal" spray I've seen. And none of it has been worth a flip. I keep going back to good old dielectric silicone like RandyB linked to. Also good to use on about every other electrical connection you have. I use it religiously on motorcycle wiring in particular as about all of their wiring is so exposed to the elements. Still open minded about a better battery terminal protector but I have low expectations.
Also helps that I have box of dielectric grease tubes, enough to last my life and then some. I was talking to a satellite installation guy and noticed him toss a tube of it into a box. He said a new tube came with every satellite kit. Since he only needed a couple of dabs of it for each one it was terrible overkill. One tube lasted him like ten installations. Ended up offering ten bucks for the whole box and he took it.