Williamson's participation at the event was thrown into doubt when he underwent surgery for a torn anterior cruciate ligament in April but he has impressed with knocks of 54 and 37 in warm-up games against Pakistan and South Africa recently.
The 33-year-old will skip their tournament opener against defending champions England on Thursday to build up his fitness, but Latham is delighted with his progress.
"It's great to see Kane back and to see him batting," Latham told reporters on Wednesday. "It's like he never left, to be honest, in terms of batting.
"It's great to see him moving really well too. He's playing all the shots he used to play.
"To see him back on the field is another stepping stone in terms of where he needs to get to in terms of his recovery."
Latham will lead New Zealand in a rematch of the 2019 final, which England won, but he said his team would treat their opener at the 132,000 capacity Ahmedabad stadium like any other game.
"Leading into a game, there's always anticipation of what it's going to be like. But for us it's about trying to do what we do really well," Latham said.
"The good thing about this group is that we stay really level and we've done that for a long period of time.
"Even though it's a massive occasion for us ... it's just another game and if we do what we do well, we'll give ourselves a good chance towards the back end of the game."
