Nox is an expert in herbology, poisons, and drugs. That alone makes her suspicious.
That's seems to be looking at it only in one perspective.
She's also considered the best healer (better than WW's specialists from the looks of it), with her tonics, brews and medicines.
Torsten also sent Astrid to request Nox to come to his house.
If he thought Nox was the one responsible, why not just say it to Astrid and Helga (I think was her name, the WW barkeep lady)?
Besides, she is kind of power-hungry, wanting to be queen and spread her cult.
I mean, so is Candrid.
Granted, she is my second favorite character, but even I can't deny Candrid is quite power-hungry and she became the Kingmaker for MC in order to place herself as Queen of the clan.
Doesn't mean she doesn't genuinely love the MC; it's just that both things (Kingmaker + love of MC) just came together at the right moment if player chose her path.
Furthermore, the clans need to be pitted against each other, given the events of the last update. At least they'll break their alliance. If WW and DR team up against BB, BB loses. If DR remains neutral, it will simply become detached from the story. The only solution I see is that DR provokes the other clans, especially WW. I think Candrid knew about the poisoning and let it happen, but wasn't the one that actually did it.
I mean, they can still have DR be indirectly responsbile while Nox not being the one who poisoned Torsten.
Yes, Nox has poisons and drugs, but Lizgard & Katja also has access to her tower when they meet her (since those two Nox trusts the most).
Lizgard I don't see her stealing the poison and being in league with Candrid.
But Katja? Yup, I can see her doing the deed.
She's already went behind Nox's back once by fooling MC into going on the raid (when Nox didn't give such an order, just that Lizgard and Katja keep MC away from her for a while).
Not to mention with the whole shift in clan members going around;
Sonja: BB to WW
Yrsa: BB to DR
there's gotta be some exodus from other clans to make it even.
Candrid seemed to be getting closer with Katja (DR) and Mathilda (WW) during the raid.
If it's found out that Katja stole a poison potion from Nox's tower, I can see Nox banishing her from DR.
But even so, DR still gets the blame and WW gets in an antagonistic relationship with DR.
Nox's mind so far for the past couple of updates have been on stopping the Ragnarok - so spending time conspiring to kill Torsten feels out of character for her, at least from my eyes.
As the saying goes, I think she has "far bigger things to worry about" than eliminating other clan leaders.
But I guess we shall see when DR update comes around.