I was looking through the coppermind and found this quote under Navani's page.
Chana is Shallan's mom. It specifically chose Chana as one of the Heralds to reference here.
Probably reading too much into it, or just Sanderson choosing her, since it's literally her mom.

I love those moments, it's why stormlight is my favorite series to re-read because I always pick up on a new little detail every time.
I’m so excited to reread since I finished Warbreaker recently. I’ve been getting through a bunch of other comers books and I can’t wait to circle back to Stormlight!
Hmm, I wonder of Chana was tied to the aspect of motherhood during her Heralding days?
What I recall from Wind and Truth is that she was a badass female fighter. She left that behind to become a mother, becoming the opposite of het Heraldic aspect like most Herald. But if that's true, why would she be invoked in OP's quote?
I don't think so
I think it's more about Navani and how far she'll go to protect her own
Basicly saying you'll need a hearld to keep you safe
I mean all female Heralds were badass fighter, it comes with the territory.
In modern Vorinism Chanarach is associated with the divine attributes of bravery and obidience, which i could see being associated with motherhood or child-rearing (though Vedels loving and healing might fit better). But in the case of the quote Chana may simply be invoked because someone would need to be very brave to get between Navani and one of her clutch.
Side note - I feel like even by WaT, Navani still doesn't quite consider Shallan to be family. In the spiritual realm she thinks about how as long as Renarin and Adolin are safe, it's fine. She fails to think about Shallan.
She's probably grouping Shallan and Jasnah together (partly because Jasnah trains Shallan): too independent and don't like being taken care of.
that's sadly true :/
whoa
I'm doing my reread and pointed this out to my boyfriend like two weeks ago! Such a cool detail.
I literally just reread that last night and was mind blown. Storms, that’s great writing.
I need to reread SA, again... And I need to hold pen and paper and write down everything, and once I am done reading, I can analyze everything. So I won't need to reread SA... Again...