Maybe you could say that Nature is the consistency of the mechanics that govern the universe; the mass of objects, the speed of light, and other mechanics that we can count on most anywhere we go. Reailty, meanwhile, is the actual configuration that emerges from Natural interactions. For example, it is Natural for me to want to get laid (since my chemical mechanics put that desire in me), but in Reality, I might not be getting laid aw often as I want (because that is the actual configuration of matter all across the universe right now). Or another example. We know that Nature allows for planets like Earth that organisms can inhabit, but there may not actually be another planet similar to ours anywhere. Regardless of possibility, Reality is what is going on, but understanding Nature can give clues as to why Reality is what it is.