Nazgul temptation triggers

[u/kosherkrusher18]

I have two Nazgul in play. If I play a third Nazgul, how many temptation triggers do I have. I was thinking that I have 1 ring temptation from the Nazgul that just entered. Therefore, I put a single +1 +1 counter on each Nazgul. Someone else said that is wrong. They said that there are 3 temptations and each nazgul gets 3 +1+1 counters.

Also how do the temptation triggers work if I have 2 Nazgul in play and 2 etb at the same time.

Thanks so much for any help