Hello guys. I'm trying to get get FAT sounding chorus like in this acapella : 1:06 minute mark  : soundcloud . com/billy-milligan/billy-milligan-a-capella (Delete the spaces in the link)
But cant reach this sound. Any ideas how the mixing were made? Panning, equing, melodyne?

Your link disappeared because you don't have 25 posts, yet.
 
Post your link not in the form of a link and someone will check it out and give you some good advice.

Thank you. Just edited the thread.

It sounds to me like the vocal at that point is doubled with a deep synth playing the exact notes, or the vocal is sampled and fed through a synth. Guessing, 'cos it's way out of my area.

Sounds like it's maybe being processed through an octaver effect send and the effect is being brought into the mix to give it a full sound.
 

any or all of the above.

I can hear that artifact sound (tone) of doubling the voice using TC-Helicon, the older rackmount model TC-Helicon Voice Works called it 'Thicken' and they have the new pedal version called VoiceTone Double. Both units basically use 'Unison Mode with Enhancement (additional effects option)'.  There is also an echo effect to help give it an overall touch of spread/filler.
 
Antares Duo Evo is another vocal processor that doubles (thicken) the vocals. Here, go to page and select Audio/Video > Audio and listen to the two vocal demos (1) Female Vocal Dry. (2) Female Vocal - Processed with Duo Evo.