Originally posted by Freedon Nadd
"I do not believe he knows his ship has been boarded, and if he did, he would not care. The extent of his power cannot be put into words, and his perceptions have grown as well. To him… you are dust motes in a storm, a grain upon the beach, and as insignificant as a body that orbits the graveyard of Malachor."―Visas Marr and Tobin (Star Wars: Knights of the Old Republic: The Sith Lords)
"His power is great, and it comes from hunger. He is a wound in the Force, more presence than flesh, and in his wake, life dies, sacrificing itself to his hunger."
―Visas Marr (Star Wars: Knights of the Old Republic: The Sith Lords)
"As Nihilus greedy consumes entire planets life energies, the dark side macerates him even faster."
―Star Wars: Knights of the Old Republic Campaign Guide
"Darth Nihilus was known as the Lord of Hunger and was noted for his ability to literally consume the Force energy of his victims, which was used to sustain his own life energies. It was rumored that he could consume the Force energy of an entire planet(Katarr as an example)
―The Complete Star Wars Encyclopedia
"And it devours him as he devours others—his mere presence kills all around him, slowly, feeding him. He is already dead, it is simply a question of how many he kills before he falls."
―Darth Traya (Star Wars: Knights of the Old Republic: The Sith Lords)
"[Darth Nihilus can] draw life energy from living beings, gradually absorbing it [himself]."
―Star Wars: The Dark Side Sourcebook
"Nihilus powers grew so extreme that, for most beings, mere exposure to the Sith Lord would cause immediate and utterly mindless devotion."
―Star Wars Insider 88: Virtual Sith
"Darth Nihilus is so corrupted in the Dark Side that his very speech causes pain and death to all who hear it."
―Star Wars: Knights of the Old Republic II: The Sith Lords Prima Guide
facepalm
Great.
Nowhere it is stated that there is no defence to Nihilus's ability which was your claim.
Originally posted by Freedon Nadd
KotOR canon has it explained that there is no defense against Nihilus' ability.
Moreover, many of these statements are just opinions of the likes of Traya or Visas. Characters' opinions are fallible.