This is pretty horrible even thinking about it. But I will stick to the possible lying part.
I mean lets compare to other incidents that were true.
He was never super hung up with mia hamm, he doesn't talk about winning saga contest as a kid that deeply over the years, pretty much anything that really went his way.
So it makes sense he might be lying but here's 2 things that know he's not.
To get China on the regular is a big deal, his whole quest in life was to get China all the time, he just finally broke down and did it and brag about it it's part of his whole life.
And the police had tohave some evidence the crime happened. Yes they put you in jail but they give you a court hearing and your next trial with a restraining order and your kicked out till the trial to figure if he did was true or not. The only way they keep you there is if they have evidence and you can't make bail.
Like caden peck, he was in jail, they had evidence that he was trying to grow shrooms so he stayed in jail. If I'm not mistaken, he didn't want to make bail cause he might of been too dumb to know about bail bond or know how bond works.
The biggest clue is that Chris actively dances
around outright denying it most of the time. The example that comes to mind is he tried employing what little he understood of multiversal theory and claimed that it was
a different Chris from another timeline that boinked his mother. This simultaneously implies that yes, it
did happen, but Chris washes his hands of the matter because it wasn't
specifically him. Even though previously he stated part of his omnipotent godhood is effectively being a multiversal consciousness and thus the idea it happened in another dimension doesn't matter because it's
still the same Chris.
Obviously, Chris isn't smart enough to comprehend that and likely forgot this claim when he literally threw himself under a bus in another dimension. But since Chris views everything that happens in his mindscape as 'canon' to reality, why make up such an elaborate excuse for fucking his mother if it supposedly didn't even happen? The mere fact this event, according to him, did in fact happen within the scope of all creation, means he can't resolve his own history with the reality he wants to project. This is true of all things that actually happened in his life - he'll whitewash and twist his version of events to suit his ends, such as how he lied about what became the Gamestop Macing incident (he claimed it was an altercation, video evidence clearly shows Chris just wanted an excuse to mace somebody to feel like a powerful woman), but he won't
consistently deny these events happened no matter how bad it makes him look.
Remember that Chris doesn't deny the mother fucking happened because he's innocent, he denies it because he's cognizant enough to have learned it's viewed poorly by everyone else no matter how he tries to spin the story. He cares only for himself in the end, as evidenced by how the jail letters had him outright wish for his own mother's death because it meant he could get 14BC to himself and that somehow would get him out of prison (even though the main reason he was arrested in the first place was him violating a protection order trough withdrawing funds from Barb's account).