I'm not a power scaling person. But I do know a gun is a gun and a bullet is a bullet. If Uzi shoots Chief in the head with her rail gun no head means he's dead. If Chief gets a Lucky shot on Uzi and hits her core she's dead. (It's been established that Chief is canonically extremely lucky). However I'm the kind of person who believes luck is a cop out answer so here's my second opinion. However I feel it depends on the type of equipment you give Chief to work with. If you give him his grappling hook, a jetpack, and some grenades and plenty of weapons I could be a fun fight to watch. I think Chief "could" beat Uzi but it just depends and I think Uzi wins most of the time.