The Nietzschean idea I like most is that moral rules and values are noting but tools in a struggle for power and domination.

Morality, even fundamental elements like the notion of "fairness", is never self-evident or obvious - even if it seems to be so. For example "fairness" or "justice", values which are dear to humanists, liberals and socialists, are what Nietzsche called "morality of the slaves". The weak individuals - which are always the majority in a group or population - join forces in order to dominate the stronger individuals. That is what Christopher Boehm called "reverse dominance hierarchy": simple folks unite to dominate (from below, so to speak) those who try to dominate them (from above).
That is the origin of morality: rules and values like "justice" or "care" or "equality" or "fraternity" were invented and took root in our collective minds to rein in all the real and would-be alphas (generally overbearing, aggressive males).

That is the name of the game, from the hunter-gatherers in the Pleistocene to Trump who would like to be in the USA what Putin already is in Russia: the Big Guy who can do whatever he wants to increase and consolidate his power - and who can get away with it. The same, of course , applies to the sphere of economy.

Nietzsche's insight was that this quasi-eternal power struggle is inevitable and even necessary (given an evolutionary framework, but unfortunately Nietzsche never really took Darwin seriously), and that all our lofty ideas and ideals depend on, and are subservient to, this power struggle; no one can escape from it, there is no place outside this struggle. You are either one of the weaker members who are always in danger of being at the receiving end of domination or aggression, or you are one of those you can tell others what they have to do.

The only promising strategy of the weak is to unite and use their number to get the upper hand in this struggle. What it does not mean is that the weaklings are the good ones and the powerful are the bad guys, because that is exactly the perspective of the "morality of slaves" (Nietzsche, as we all know, wanted to counterbalance and replace this with a "morality of masters". I suppose he and Ayn Rand would have got along very well...)