"Nullifies anything" - Thats still a NLF. From what I read, he is just immune against all psychic powers that work directly on him, with no real feat against beings on Strange level. Is there anyone Kharn has ever fought that is even roughly on the same level as Strange ?
"and the Blessing of the Blood God, which symbolizes Khorne always watching over him and putting a stop to anyone trying to combat his champion outside of direct and honourable means." - If thats a fight between two characters, then any outside help is restricted, or is Strange allowed to merge with Eternity ? (I know its a bit difficult, since his "Psychic Resistance" comes from Khorne, but I think that it should be on the level it is in generall portrayed).
Strange hax is rooted in magic, just like most higher powers are basically high levels of reality warping. But: Using magic to attack oponents with energy, doesnt makes the attack magical and should do damage to Kharn. (On this point we are basically argue what magic is, which is basically a dead end).