Hughie has shown himself to actually not be a bad fighter, so if things get up close he'll be able to hold himself
That being said, Richie has a better weapon here. A boxcutter has pretty much no range & doesn't cut very deep, so if you want a kill, you have to hit something vital that's surface level, like the neck. Richie's knife has more range as well as a bigger blade that lets him cut deeper than Hughies. And Hughie's shield can be pretty easily dissarmed due to Ghostface's superior LS. I don't remember how good Richie was at stealth, but if he's competent at all, I don't see why he wouldn't just be able to sneak up behind Hughie & slit his throat, even with Hughie knowing about the possible sneak attack
Honestly might have to go against the tide & say Richie here. In any physical confrontation he can easily overpower Hughie's 10-B AP & Average Human LS, with really his only worry being Hughie's stamina & Wall level durability, but a good stab to the throat would solve both of those issues. A knife beats a boxcutter in a fight every time, and Hughie really only has a chance with the shield, which can be easily disarmed. From there, it's just a matter of time until Richie just manages to stab Hughie enough for him to bleed out
I'm voting Richie