This is a difficult one for me, but I think it would be a tough battle that would ultimately end with the Hoff cleaning Norris' clock with one of his patented punches.
KITT would succed in convincing The Hoff that there is no need in fighting Chuck Norris, because they're both on the same side of law and order - just in time before The Hoff knocks out the Chuck. Then The Hoff would thank KITT for bringing him back to his senses and being reasonable again. KITT would reply with a quote from one Rick Astley: "I'd never give you up, I'd never let you down", which would have even Chuck Norris smiling again.