Mystic Gohan would crush Broly, going by power scaling.
Although SSJ2 Gohan in the second Broly movie did better than anyone who had ever fought him, he was still very obviously outmatched, only managing to wound him once, with it requiring IIRC something like Gohan, Goku, and Goten's combined powah along with a distraction from Trunks to overpower his blast.
So I doubt the unknown advantage in power Cell Arc Gohan has over the one Broly fought will fare much better.
Even though it's totally non canon fan fiction, I kind of like how Dragon Ball Multiverse made Brolly with a Juggernaut class force field, and just regularly kept powering up into infinity.. Even SSJ3 Vegito couldn't actually kill him, only battlefield remove him on a really powerful ki attack.
Gender: Male Location: home, playing Guilty Gear Xrd.
I'd have to say Broly. he did shrug off everything thrown his way. not too sure the same could be said for ss2 Gohan if he got hit with everything they hit Broly with. and of course because Gohan's power is much greater as ss2 than in ss, he should probably take things a bit more seriously.
Gender: Male Location: home, playing Guilty Gear Xrd.
well I never did say Broly would easily win, but he'd certainly have to put more effort into it than he did against the z fighters in movie 8. however, if Gohan doesn't take him down fast, Broly will just grow stronger and that could turn the tide of the fight.