Battalion — Whenever Nav Squad Commandos and at least two other creatures attack, Nav Squad Commandos gets +1/+1 until end of turn. Untap it.
Once a battalion ability has triggered, it doesn’t matter how many creatures are still attacking when that ability resolves.
The effects of battalion abilities vary from card to card. Read each card carefully.
The three attacking creatures don’t have to be attacking the same player or planeswalker.