As for her chances... well, before the Holly-Ronda fight, I thought Holm's chances against Cyborg were slim to none. A tiny chance of her getting a point-and-run decision, but most likely an easy takedown-and-gnpTKO for Cyborg. Then the Ronda fight happened. After that my opinion changed a bit. While I'd still expect Cyborg to win, I wasn't quite as sure anymore. Not because Holm knocked Ronda out (I don't really see that happening vs Cyborg) but because of how well she handled Rousey's aggression and used it against her (and also a bit because of how easily she shrugged off Rousey's takedown (and sub) attempts). Now after Holm's recent - not so impressive fights - I tend to lean way more towards Cyborg again, especially with Cris apparently wanting to put more and more focus on patience. Tbh I wouldn't even rule out Cyborg winning via decision.
I still think Holm is probably more dangerous to Cyborg than pretty much any other fighter (including deRandamie, even tho I also consider Germaine to be having better chances than most others).