All summer, Kristaps Porzingis worked on getting stronger. He lifted weights. Ran. Boxed. He wanted to evolve into what Pistons coach and executive Stan Van Gundy recently predicted for him.

“He’s going to be a nightmare for years to come in this league,” Van Gundy said.

So far this season, opponents are losing lots of sleep over the Knicks’ 7-3 Latvian. Next, it’s Houston’s turn to combat him, Wednesday at the Garden.

“Some of the stuff he does,” center Enes Kanter said, “we just look at each other on the bench like, ‘Man, did he really just do that?’”

Like going up nearly into the rafters to flush an offensive rebound. Or draining a 3-point shot seemingly from Times Square. Porzingis, 22, has evolved frighteningly fast in his third season.

Porzingis is growing, literally and figuratively. Monday, he demolished Denver with 38 points, scoring inside and outside. At his size, he simply shoots over everyone, although the Statue of Liberty might present problems. But he’d probably just drive around what Knicks fans consider France’s second-best gift to America — right behind Frank Ntilikina.

“The biggest thing is him getting stronger, then him understanding his spots on the floor and where we got to get him the ball,” said Courtney Lee. “Anywhere between 15 to 10 feet on the floor, that’s his money area. He wants to get the ball right there. There’s nothing you could do once he puts it above his head to shoot it. So it’s him getting stronger and being able to get that position, then us just being able to execute and get it to him at the right time.”

There have been some nice results. Like five 30-point games in the first six of the season. No Knick — not Willis Reed, Patrick Ewing or Clyde Frazier — ever managed that. In the past 25 years, only two other players achieved it: Toronto’s DeMar DeRozan did it last season and Milwaukee’s Giannis Antetokounmpo also did it this year.

Size, strength, positioning. The Knicks’ new leader, Jarrett Jack, helped the positioning. After the Knicks were crushed in Boston by the Celtics — the one team that used aggressive double-teaming throughout and snuffed Porzingis (3-of-14 shooting, 12 points), Jack went to him. About to be inserted as the starting point, Jack told Porzingis he would get him into the proper spots and get him the ball.

“It was on the plane. He and Willy [Hernangomez] were having a game of Monopoly, but I thought I had a bigger conversation for him,” Jack said.

So build your Boardwalk hotels later.

Since Boston, Porzingis has shot 40-of-77 (.519) and scored 100 points (33.3 per) in three games. If that’s not a nightmare, what is?

“I’m just playing my game. I’m trying to be aggressive and doing things I know how to do, I know I can do on the offensive end,” Porzingis said. “Defensively I’m trying to bring some energy. … I’m playing well.”

Playing well? Yeah, and New York City has some people.

“He’s 7-3, can handle the ball, run the lane like a wing. You can’t really … I’m lost for words,” Tim Hardaway Jr. said.

“It’s maturity. He’s up for the task. He knows what’s ahead of him and what we expect,” Lee said, referencing Porzingis’ summer training. “He was working in the weight room on his body. He’s going to continue to do that, continue to get better.”

So far, so great.

“My strength is helping a lot. Just having my balance on all those shots,” Porzingis said. “Even though a lot of those shots are contested, I’m able to make them through contact. I’m just more comfortable in the post.”

So far, nothing except Boston Leprechauns has stopped Porzingis, especially on his turnaround jumper. Or his put backs. Or his 3-pointers. Or anything, really. The turnaround, though, has been deadly.

“I’ve been doing it my whole life. It’s something I always work on. There’s still a lot of things I want to learn in the post,” Porzingis said. “I always say keep it simple. … Just using my length, I’ll be able to shoot over guys 90 percent of the time.”

And be a nightmare 100 percent of the time.