If it's current Nefaria then Lobo takes this with ridiculous ease. But I'd argue that you can't really strip the toonforce from Lobo. That's like taking the Power Cosmic from Surfer or taking away Batman's self-righteousness--it doesn't work.
“Where the longleaf pines are whispering
to him who loved them so.
Where the faint murmurs now dwindling
echo o’er tide and shore."
-A Grave Epitaph in Santa Rosa County, Florida; I wish I could remember the man's name.
Nefaria is physically superior to Lobo, he will win. No way is Lobo capable of fighting Thor, Wonder Man, Iron Man, Capt America, Scarlet Witch, Wasp and Black Panther as well as Nefaria did. Personally, I wouldnt even give Lobo the vote to beat Thor alone, let alone the rest of the Avengers.
Lobo took on Justice League Europe by himself, so I wouldn't put it past him. His only threat would be in Thor. The rest he'd beat the hell out of. I could actually see him rip Tony out of his suit of those days.
Lobo easily took out a guy that was arguably more powerful than the Thing. I mean he ripped the rock off of the guy. It was when he fought the L.E.G.I.O.N just before Braniac removed his cloning ability.
JL Europe had Captain Atom, Martian Manhunter, Guy Gardener and a few other powerhouses. They weren't weak. The reason why Nefaria wouldn't beat Lobo, is because Lobo doesn't fight fair. He'd punch him in the nutz and while the Count was winded, he'd kick his teeth in. Lobo would do just as well against that Avengers team as Nefaria did. Don't get me started on the beating that he'd give Simon.
Nefaria hasn't been his best under Bendis, but then again Lobo has had much worse showings than Nefaria.
Classic Nefaria though? He's stronger and tougher than Lobo but he's a bit of a coward until he got some time to adjust. He might be able to just beat Lobo up and down the planet, but under some portrayals that wouldn't keep him down due to his insane healing factor. On the other hand he could just straight up knock him out, even ridiculous healing factors don't make you immune to knock outs as Lobo himself, Hulk, Wolverine etc. have shown (Does increase resistance). Tough call, depends on what version of the healing factor you're going with I guess.