Jack Nicklaus is the greatest golfer of all time, so it's only natural to want to copy features of his game. Go ahead and borrow Jack's tremendous competitiveness, his poise under pressure, his superintelligent course management and his putting stroke.
Do not, however, try to copy his golf swing.
Imitation is the sincerest form of flattery. Over the years thousands of golfers have tried to copy Nicklaus' unique swing method. Of those, only one talented professional--Mark McCumber--has been able to copy Jack's swing successfully. That's because Jack swings the club very wide and very high, a tough combination. You might have luck swinging one way or the other, but for the average player to implement both is almost impossible.
The wide and high backswing enabled Jack to hit the ball inordinately high and far when he was younger. He was massively long and had a distinct advantage over other pros from the rough. It all was due to that wide, high backswing and a unique method for hitting through the ball.
Jack's swing has not aged very well because he doesn't have the strength and flexibility to swing the way he once did. He's adapted by making a few changes, as you will see. But he's maintained certain movements in his swing that are dangerous to copy. The way his right elbow separates from his torso on the backswing and the way he switches from an upright swing plane on the backswing to a much flatter one at the beginning of the downswing are good examples. But Jack is the greatest golfer who ever lived, and parts of his swing merit duplication by everyone.