First a little disclaimer: I am NOT an engineer, so this just an opinion.
The stock CBX swingarm is not a strudy piece. It may be prone to twisting when cornering aggressively. A wider tire will only make matters worse as it moves the forces farther from the centerline as we lean farther. So, unless you are riding hard enough to run out of traction, a narrower tire will handle better.
However, if the change is mostly cosmetic, go for as wide a tire as will fit. Just realize that the bike wasn't designed for that tire.
Rick Pope: ICOA Rally Director.
Either garage is too small or we have too many bikes. Or Momma's car needs to go outside.