"Big Game James" just dished out some serious praise to Lakers rookie Lonzo Ball -- telling TMZ Sports he's REALLY excited about the kid ... and gave him one of the best compliments ever.

Of course, Worthy was Magic Johnson's running mate back on the Showtime Lakers in the '80s -- and has been heavily involved with the Lakers organization ever since.

So, for James to heap that kind of praise on Lonzo is a pretty big deal.

We know what you're thinking -- is James dissing Kobe?

We don't think so -- seems more like a pure point guard comparison to us.