Is the nova sorc better with self use infinity or infinity on mercenary ? I cant decide

Sorc holds infinity
Merc holds insight

Better how. Define better.

Like is it gonna have mana problems without insight with the self use infinity?

Yea, nova is an eshield build and requires insight.

It's also worth mentioning that while eshield nova is flavor of the month, vita lightning is still stronger at players 8.

Stronger in what way?

Damage. With lightning, players 1 and players 8 feel similar on a fully geared sorc. With nova, it takes a lot more hits to kill stuff on p8.

Self wielding infinity with merc using insight is simaltaneously the highest damage and highest survivability setup.

Sounds better to me

I think this might be true as well.
Ormus Robe nova with a 2/20 amulet.