He's top 3 tied with Datsyuk and Shipachev, he's on the 2nd line with Shipachev and Dadonov and on the 2nd PP unit but he only plays 14 minutes per game. He's got a complete offensive arsenal. A lethal wrister with an effective one-timer, his passing game is excellent, he's got the stuff to find open space in the scoring chance area in 5v5 situation and he can burn you with speed if you don't have a proper gap control.
On the negative side, his apparent physical softness could be a problem on a smaller rink but I'm just guessing, the KHL is really a very competitive league and to play on the wider rink has its own issues too, but he's flying out there against grown men. He clearly needs to improve his all-around game nonetheless. The good news is that you can teach to play acceptable defense but offensive skills on Gusev's level cannot be taught. At the condition he'd make the jump I can see a problematic translation to the NHL at the beginning, particularly under Cooper, but I have no doubt his offensive skillset is for real, even for the NHL and would produce right off the bat. Like many skilled, finesse players Nikita is kinda hit or miss, he's either a top 6 forward committed to learn a bit of the N/A two way game and ready to take physical abuse, or he'll be nothing.