In character, Broly wins 10 times out of ten. I'm including Ultra Instinct in this scenario. The thing with Broly is that he literally seems to have limitless and rapid growth in speed & power, so the only way to stop him from going further is to kill him. Goku would never do that if there were no stakes and end up losing.
Even out of character or with stakes, I still think Broly is likelier to win because he's already gained the durability to tank everything SSB Goku & Golden Frieza can throw at him. Beyond raw strength, Broly is also a deviant when it comes to learning. I think it was his father who said he wasn't adjusted to fighting humans, and moments later Broly gets the hang of it and starts slapping Goku's ass despite Goku being trained in martial arts. Ultra Instinct doesn't offer the ability to evaporate Broly as far I know and SSB Goku definitely isn't capable of doing it. Maybe manga Goku could use Hakai on him.