They've been very bad throughout the entire group stage and should count their lucky stars they qualified. Their defence is extremely unconvincing. I can't see them getting past France, in all honesty.
Argentina monopolised possession, yet weren't passing it with enough speed. It was too slow at times.
Part of the reasons for this were when Argentina played without a midfield at times. It was like a 5-0-5 out there. Very risky. They had no proper link between midfield and attack, until Banega had some common sense to drop a bit deeper in the final 15 minutes.
Nigeria employed similar tactics to Croatia in congesting the middle of the pitch and doubling up on Messi, and for most of the game it worked. But Argentina didn't utilise their width enough. Only when Pavon and Meza came on is where they stretched the Nigerian defence. And when they eventually did get into promising positions, the final ball was lacking quality.
Too many players wanted ball to feet, rather than creating space for others.
Nigeria counter-attacked quite well, Musa in particular was causing them problems. Ighalo missed some absolute sitters though, and it goes without saying that a team of better quality/maturity would have finished them off.
Overall, very unimpressive from the Argies.