The new Nazimuddin does seem to have pretty good temperament, seems to look to middle the ball early on and has a decent stride forward - which is a huge contrast to the version that made his debut in the shorter formats a few years ago.
Two things might have gone in his favor so far in this Test match. For one, he has been made to work extremely hard to regain a spot in the national team, which probably forced him/gave him the opportunity to go back to the drawing board, take a serious look at his flaws and put his head down and fix them. He knew his chances of making a comeback were low and he sucked it up and did what he had to.
Secondly, having featured in the NCL every year has probably provided some sort of continuity, which he has been able to bring in to international cricket. Given how our national players don't have to fight as hard to keep their places and how they hardly ever play any games when not on national duty (national duty hardly counts as match practice when you only survive two deliveries per inning), it comes as no surprise that they suck big time.
Give Nazimuddin a year, and he will likely turn into an Ashraful or a Mofees. The only way to fix this never-ending cycle is to ensure that the NCL is long enough that the players get enough domestic cricket when they're not busy failing for the national team. This should give them some breathing space so that they can work on their games in a competitive setting without the "burden" of having to perform in international matches and will provide some much needed continuity.
Screw the IPL, I'm going to the MLC