Difference between Nash equilibrium and Pareto Efficiency
I wouldn't say Nash equilibrium is broader than Pareto-efficiency I'd say its different. As all know the sole Nash equilibrium in the Prisoner's dilemma is not Pareto-efficient and the three Pareto-efficient outcomes are not Nash equilibria. That is to say there is no intersection between the two terms and hence none can encompass the other.

I think the main difference comes from the fact that Pareto-efficiency is only concerned with outcomes and not with the mechanisms of strategic interaction. The Nash equilibrium takes this mechanisms into account explicitly. I.e. you cannot obtain a Pareto-efficient outcome in the Prisoner's dilemma as the other player will preempt it.

My advice is: don't read about Game theory on Wikipedia! The first homework in the master's course on GT at my faculty is to find an error in a Wikipedia article on GT and correct it.