China purchased a T-10K prototype from Ukraine, from which it developed into J-15 with its own experience manufacturing the J-11 family. Russian Su-33 is also developed from the same prototype, thus they both have the same parent. However, to say one is copy of another is simply laughable. Nobody would be stupid enough to call your younger siblings a genetic copy of you.
Furthermore, the Su-33 was developed in the late 80's to early 90's. On the other hand, J-15 was developed in the mid 2000's, taking advantage of improvement in avionics and material development since. It's not surprising that it would be superior to its older brother.
However, if this was just an Indian attempt to troll, then let them continue down their path of retardation. Maybe they'll be happier when their exploded boilers are repaired.
The distinct nozzle of WS-10A.