Question: how do miners and nodes interact? What happen during a 51% attack?

Hi, just want to understand the importance of nodes vs miners.

In Jeff Booth article https://bitcoinmagazine.com/culture/bitcoin-signal-in-this-noisy-world he says:

" while miners compete as economic actors to secure the network, they are held in check by nodes (open to anyone to easily set up and run) who confirm the transactions "

how does having ALOT of ppl running these nodes help keep the miners in check? I understand it confirm the transaction but does that do anything? In an even of a 51% attack, how does these nodes help?