ill try and find if george specifically said it (which im fairly certain ihedid) but many EU guides which are very much canon state this. And Luke has an impressive list of feats. That back up the claim. I take it that you are very unfamiliar with luke other than what you see in the movies.
either way, people said nilihus consumed whole planets but when i say that you immediatly jump to say that there is no proof. but it's on a lot of sites reapeted so that doesn't mean it is wrong. but me, i never heard of luke doing that...i rarely think about luke as a jedi because i didn't like many jedis other than qui gon, anikin, kinobi, mace, and yoda i also thought he was kind of a wussy ignorant kid to be honest...cus he was always asking questions in the movies and afraid of alsorts of stuff.
oh come on...Sideos was at the brink of death anyway and it was vader who helped him by betraying him. and a black hole?!?!? i have little doubt in my mind that Nilhus could do that too.
I doubt he knows much of th EU (which is very much canon) And in the DE comics the were being described as fighting as avatars of light and dark respectively.
Just a note: Lucas has apparently stated that the DE-comics were the closest thing to his idea of a sequel-trilogy. That's something you should all consider when discussing the EU....
Luke at his peak (probably in NJO) is >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>than ROTJ version of himself. And Nihilus is NOT capable of manipulating a black hole. He had very strong tk and a force killer technique but other than he has nothing on luke. And just because he has one massively uber technique that no one else has doens't mean his others will rank anywhere close to it. And seriously have read much of the eu? cause it explains how luke becomes into a force god.
I don't think he's ever actually said that. But, he clearly regards Luke as the best (not necessarily the most powerful) and his most dear Jedi, since he's botched every attempt the EU has made to kill him.
Those two were huge and the thrawn trilogy in particular gave star wars a boost along with the De comics reinvented star wars. Personally i love sidious's intellect and how manipulated he is to take over the galaxy without declaring war on it like other sith have done such as revan and exar kun.
There is way more than enough evidence for him, if sparrow disagrees than he can make a vs. thread and see what others (who know MUCH more than i do about luke) and