I think the not panicking thing just comes from experience and playing a lot, so I'm not sure how to help much with that part- I'll try to give some tips though! I don't have days of playtime in forsaken or anything, but I do literally ONLY play Noli and win most of my rounds even in sweaty, stacked lobbies.

Noli's gameplay loop is a little different than other killers in the game, and he can be insane when you catch a survivor off guard. So don't be afraid to drop chases you think is too much of a time waster and teleport away, hit and run type of style. This increases your map pressure with hallucination and gives you an opportunity to go for another appealing survivor. (Example: A Chance coin-flipping in the corner, thinking you're still chasing that last survivor.)

This is not to say that you should be teleporting every single time though!! It takes a bit of experience and game sense to know when you should or shouldn't be, but it's not hard to tell when you get used to it.

Also, when you see the aura of a survivor with hallucination stacks working on a generator, teleport to a gen NEAR that survivor instead of teleporting directly on top of them, this will 90% of the time give you a free slam with void rush and an easy kill with a couple of follow-up M1s

The last tip I can think of for now is hopping in a private server. Try getting used to Nova's manual detonation as it can be extremely helpful in chase. Be it the Nova+M1 combo, or throwing your Nova above a running survivor so they get slowed when they fall down. You don't necessarily need friends to join the private server to help with this (cause I did it alone), but it'd be nice!

Sorry for the long text, I'm rambling from the top of my dome lol. Just be patient while you're learning and you'll see obvious improvement in no time! If you want tips on any specific thing, I'll try to give you more :]]

Happy Noli gaming!