> all of our tax dollars to NATO

Total US spending on all defense, not just NATO, is ~$900 billion or ~13-14% of federal spending. NATO has a total annual budget of less than $4 billion and we cover something like 15% of that budget, less than 0.001% of military spending and some infinitesimal portion of overall spend.

> for nothing in return

The US gains incomparable wealth from controlling the global prime currency. Part of the enforcement of this primacy is 750 military bases in 80 countries, giving the US a force projection capability greater than any empire in human history. For the US, NATO is just a just an organizational tool to manage resources among it's allies.