What is the best move here? Where do I move knight?

Moving the knight to a5 seems best to me.

Was that position from a game of yours?

Ne5

skotheim2 if I play e5 and knight takes, then what? Recapture with pawn? If if so, this means my fienchetto is blocked by my own pawn.

For that reason Na5 looks like the natural move to me. If it doesn't work for some reason (have to calculate after bishop moves threatening b4 next) then I'd look at Nb8 next.

1...Nb8 looks best, if you follow it by 2...Nbd7.

I think 1...Na5 is quite bad, since after 2.Bd3 you will most likely have to play ...b6 and ...Nb7 to save your knight from b4; 1...Ne5 is terrible after 2.Nxe5 dxe5 (for many reasons, including the fact that you obstruct the e5-square which could have been occupated by a piece at some point, but also because you weaken your queenside, you obstruct the fianchetto, and if one day White plays b3-Ba3, the a3-f8 diagonal is really weak); 1.Nb4 doesn't look so great either.

I agree if you have to save it with b6 that it's bad. I was thinking some discovery on the diagonal or protecting c4 to let the knight go there.

Maybe I should say,  Nb8 looks natural, but Na5 is worth calculating.

Oh you're right, I hadn't seen it. But even if it's tactically justified (which I doubt a bit => two knights may not be worth a rook and a pawn), I don't know whether it's so good to put the knight on the edge of a board where it doesn't really have many prospects.

Is this an on-going game?

Ne5 is not bad

Uh, not sure 3.f4 is good in your variation. If I played the White side of this, I would really try and avoid to free up Black's DSB. Maybe White's advantage after 1...Ne5 should rather be converted by playing on the c-file and the queenside (f3-Be3-Rc1 etc.).

Ne5 seems like the only playable move, other knight moves give white a huge advantage

Well, at first I was thinking Na5 Bd3 e6 and b4-bxN doesn't work because black captures both center pawns... but ok, calculate that out and it wont work.

So then e.g. Na5 Bd3 a6 (for b5 to protect c4) and now if b4 then Qc7 counter attacks and protect c4.

But the queen may not want that file so instead of a6 B-moves with Rc8 is another idea to protect c4.

But these may or may not work due to tactics. If it doesn't work, then, IMO, Nb8 is much better than Ne5.

Yeah, I didn't think Nb8 was so bad, but of course it is undevelopment so I guess it's not a surprise it's not good.

I would be afraid to play Ne5, but maybe it's not as bad as I was thinking.

That's what makes chess fun heh.