The Sicilian is a very theory heavy opening. These variations go over 25 moves deep. It all depends on what you want to achieve and which line you want to use, how you want your middle game to look like etc. And more or less they are all fine and it depends on your preference. Personally I don't play either but go for e6.
Should I play d6 or Nc6 after Nf3 in the Sicilian?

"... I will try to predict the future course of developments in the theory of the Sicilian, over the near future. … 1.e4 c5 2.Nf3! d6?! 3.d4! cxd4 4.Nxd4 The more deeply we study this position, the more apparent White's advantage will become. … The main theoretical battles in the Open Sicilian will come in … : 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e5! …" - GM Evgeny Sveshnikov (2014)
Hi, I would to know which is better, d6 or Nc6 in the Sicilian after your opponent plays Nf3. In a bullet game, I don’t have a lot of time to think about it. I need some help so that way my brain doesn’t have to fight and waste time. Please help me so that I can be better when I play the Sicilian.