If I'm not mistaken, Kaneki has the stat advantage by an unknown amount (He one-shots 16 tons, but I don't know the one-shot range Tokyo Ghoul uses, & the 7.5x is only for determining the value to One Shot within Versus Threads in the absence of known ranges, IIRC.), unless Killua scales sufficiently above his 22.13 tons scaling point.
Kaneki also has Regeneration, & Resistance to Electricity Manipulation, & Killua will probably lead with Electricity Manipulation, especially in this key; Part of his training was developing an individual Nen ability, & he developed the ability to Transmute his own Nen into Electricity, as well as absorb & harness it from external sources, so he'll probably lead with that.
Killua likely won't try to "Nen Crush" until after he realizes Electricity Manipulation isn't effective, so Ken probably still has a window of opportunity where he can win before that.
I mean, presuming it isn't always active.
& even if Ken CAN'T perceive where the Nen is (Mind you, you don't need to be able to see Nen to be affected by it.), it's still possible he could avoid the effects by being out of range. He might know nor be inclined to do so, but it's a possibility, & usually, Nen users don't spread their Aura out very far unless it's for part of an ability, or for sensory purposes like using En to detect stuff; Since Nen is what you also use to defend yourself in some ways, &/or augment your attacks & such, I doubt Killua would be inclined to spread it out very much early on.
& of course, this probably isn't accounting for the close quarters match-up.