Which countries did NATO invade again? There’s the operations after the break-up of Yugoslavia but that was largely a Peacekeeping operation. Do you consider that to be an invasion?
Afghanistan was most certainly an invasion. That happened because one of NATO’s members (US) was attacked. Yes NATO will invade countries when a member has been attacked.
Sure there’s no-fly zones and some airstrikes conducted by NATO, but in terms of outright invasions, it’s just Afghanistan which was in response to a member being attacked. Because it’s a defensive alliance.