CHICAGO — Two painful years of tanking.

Two even worse lottery heartbreaks.

The Nets suffered lousy lottery luck for the second straight time, entering Sunday with the joint-best odds to win the No. 1 pick but tumbling all the way down to sixth in the draft.

In a generational draft with three perceived franchise changers at the top — BYU’s AJ Dybantsa, Kansas’ Darryn Peterson and Duke’s Cam Boozer — the Nets will miss out on all of them.

They’ll have to rely on finding a gem further down in a deep class.

“Yeah, sure. Look, we’re going to debrief on it. And we’ve already been prepared no matter where we were picking in this draft,” Nets general manager Sean Marks said in the aftermath.

“And there’s going to be some really good options for us, whether we are picking one or whether we’re picking 10, right? So I think with multiple assets that we have in this draft, multiple future assets, we’re going to continue to build this team up into hopefully something we can be really proud of.”

While Marks was diplomatic and composed afterward, privately several Nets sources fully understood the gravity of the situation.

The Nets had tanked their way to the league’s third-worst record at 20-62, tying them with Washington and Indiana for the best odds to win the lottery (14.0 percent) or land a highly coveted top 3 pick (40.1 percent).

But after sliding from sixth to eighth a year ago, they fell from third to sixth Sunday.

When Brooklyn shipped Mikal Bridges across the East River to the Knicks and committed to tanking — a path that owner Joe Tsai had initially opposed — they paid dearly for the option to do so.

The Nets gave Houston three first-round picks and a swap to reacquire control of their own natural picks these past two years.

But in those lotteries they have now moved down a combined five slots in luck that can only be described as horrid.

“We picked eight last year. We’ve never been that high,” Marks said. “Now we pick sixth this year, so that’s another option for us to pick higher and higher and continue to build and add talent to the roster.

“So I’m looking forward to the debates and discussions that we have with our coaching staff and all our scouts about seeing who fits, who fits now, and who we need to have a little more patience with. But who could immediately come in and be an impact player, because there are those guys in this draft.”

The sixth spot had actually been their likeliest landing spot at 26.02 percent.

But the lottery has rarely been kind to the Nets, with top 8 odds 10 times and only moving up twice.

They couldn’t make it a third, despite having Tsai as the only owner in the drawing room, Hall of Famer Vince Carter on the dais and even venerable superfan Bruce Reznick — colloquially known as Mr. Whammy — in the studio, having made the trip from New York.

“You see that up there? The Nets are 14 percent?” Reznick told The Post beforehand, pointing at Brooklyn’s odds of winning. “I’m going to change that to 100 percent.”

If only the Nets had been so lucky.

Now Brooklyn will miss out on the franchise changers at the top of the draft, and choose from a host of guards like Houston’s Kingston Flemings, Arkansas’ Darius Acuff Jr., Illinois’ Keaton Wagler and Louisville’s Mikel Brown Jr.

Does missing out on a top 3 pick to build around force them to pivot and be more aggressive on the trade market?

“Hard to tell. It’s all about how these guys develop,” said Marks. “I don’t think you want to make rash decisions before you’ve seen how they look. We all know there’s a group in this draft that could be game-changers, but I said ‘could be’ because you never know … There’s always surprises.”

Now it’s Marks’ job to find that surprise.