Ok, think on this for a moment. For those who have heard of the game, you all know the story. For those who haven't, Joker basically tricks Superman into killing his unborn child and his wife, Lois Land, and destroy Metropolis with a nuke, causing Clark to become an evil dictator. After playing the game, some may be satisfied, but I know I am not the only one who is still asking this question: Who gave Joker the nuke in the first place? Joker and Harley are easily capable of planting the trigger in Lois and linking the nuke to her heart, but they stole the submarine and somehow placed the nuke in the heart of Metropolis. They'd need to leave the sub to do this, and by the time they get back, there would be a rock in their plan: someone would've found the sub and would most likely call it in, therefore the cops would find Lois and call Superman. So someone had to have helped them with that part, because this is a rock Joker would've likely saw coming. But who could've helped him?
Simply put, he would need inside help on this part of his plan. But what Leaguer would be so cruel to help that monster. Originally in the comics, Cliana was the hot topic. Everyone loved the pairing of Superman and Wonder Woman. But this was dropped, and Clark's lover was replaced by a mere human named Lois Lane. No doubt Diana would be a little jealous, but being a warrioress, would hide her jealousy easily. Her jealousy would only grow even more as Lois and Clark grew closer, and it would reach even more dangerous levels when they get married. Bruce Wayne and Diana Prince are Clark's closest and most trusted friends, so he wouldn't just tell Bruce about Lois being pregnant, he would also tell Diana. After containing her jealousy for so long, this would ultimate be Wonder Woman's breaking point. The man she once loved who had eventually fallen in love with a mere mortal was having a child with said mortal. We all get jealous when our lovers fall for someone else, and some people can only take so much jealousy before they finally snap. So Diana would do something so cruel she would do anything to have Clark to herself once more. But this universe's Lex Luthor is good friends with Clark, so she couldn't go to the iconic person people have associated with villainy. So who would she go to? The person Batman was always so close to snapping and killing - Joker. Diana would eventually go to him and get rid of anybody at the meeting that Joker "set up". Joker being at the spot was out of place as he always prefers to try and hurt Bruce to get him to snap. Diana would then help them take over the submarine and take the nuke to the heart of the city. She would know where to go to get answers. Did anyone else find it weird that she went to the docks even though she didn't know Joker would've been underwater?
After Metropolis blew up, who was it that told Clark where to find Joker, and remind him that Joker was behind Clark's mistake? Diana was. I can only imagine what sort of hurtful she would say to the dead Lois. Everything else fell into Diana's plan. She always manipulated Clark into killing someone who didn't deserve it, and remember when she told Clark to kill Manhunter as she was getting through to him?
In Injustice 2, Scarecrow sprayed Diana with his fear toxin, and we saw that she feared she had turned Clark into a villain, even Dr. Crane said so. Or so he thought. What we saw wasn't Diana fearing she had turned her closest friend and lover into villain, she was afraid he might find out that she gave Joker the nuke and took everything from him. But we know that from his time in prison, Clark was beginning to heal. From this healing, he began to become more immune to Diana's deception, and was even so close to reigniting his friendship with Bruce. Clark was clearly almost fully healed, until Diana showed up and destroyed all the progress he had made in healing. It was her way to keep Clark away from the truth.