Laws of nature do two things for us. They delineate what is fixed beyond the power of physical beings and they are universal generalizations that explain their instances.
But there is no need for these two functions of laws to be united in a single concept. There are explanatory universal generalizations that do not limit powers. For instance all life on earth is based on DNA or RNA. This is an explanatory generalization, but it is not limiting of powers: there is nothing physically or biologically impossible about producing life with neither DNA nor RNA as far as we know.
One might link the two functions by using the power-limiting aspect to ground the explanatory aspect. Why does this particle not move faster than at the speed of light? Because no physical being can make it so that (and no non-physical being did).
But it is difficult to explain the power-limiting aspect of laws. Humeans basically just give up on it. A main alternative is to take it as primitive.
But why not just give up on the concept of laws and keep separate the ideas of limitations on powers and of explanatory generalizations?
The limitations on powers are just that: physical things not having the power to do such-and-such.
And what makes the explanatory generalizations explanatory on this view isn't some sui generis nomic explanation, but simply one of the other accepted forms of explanation. Why does the platypus and the gecko have DNA? Because they evolved from a common ancestor that did. Once we fill out a causal story we have a perfectly fine explanation here.
Now it's going to be harder to use one of the non-nomic forms of explanation in the case of something more fundamental like the conservation of mass-energy. But not for the theist who can say that God had as such willed that mass-energy be conserved, since then explanation by subsumption under the conservation law gets its explanatory oomph from a standard mode of explanation, namely the agential one.
It is tempting to try to combine the notions of power-limitation and explanatory generalization into the concept of a law. I doubt this will work. The universal generalization that all who die with their will full of charity will see God is power-limiting--no one can stop it--and explanatory. But it's not a law of nature.
My suggestion is to keep the notions separate as separate as their tasks.