The CB750 nighthawk was chain driven. That's definitely the Honda 750 DOHC engine. Maybe not a Nighthawk, but definitely a 750 Honda. Perhaps the CB750F? Regardless, it's a personalized bike, beyond whatever it used to be. It's not a bike the OP can go buy from a dealership.
1992 Honda Nighthawk 750
From 1982 through 2003, with the exception of several years, Honda produced a CB750 known as the Nighthawk 750. Early models were designated the CB750SC Nighthawk while later models were simply known as the Nighthawk 750. The Nighthawk 750SC had a 4-stroke engine with a 5-speed manual transmission, chain drive and has front disc and rear drum brakes." Wikipedia
Most of the bikes I see used to achieve that style of café burner are mid 1970 - 80's CB 750's.
Easier frame to hack up than the nighthawk if you want a similar (or better IMO) build on the cheap.
Hacking off those big ugly nighthawk tails might make a few bikes look a little nicer though too.