That looks like a sleeveless version of a judo hip throw called sode tsurikomi goshi
usually done with a sleeve grip (sode is sleeve)
Hmmm...classically though, STG has both uke and tori with feet parellel to each other upon kake, whereas the throw I cited has tori perpendicular to uke; that's one ready difference
I'd be suprised if people had seen koshi nage (per Ronda Rousey clip) in judo circles that frequently; I've seen it perhaps half a dozen times in the last 13 years.
What I have more frequently is something like this -
which is a technically a seoinage
In any case - I'm glad to know the 'oh god, oh god' technique has an *actual* name, so I can better track down variations etc. I think it's a nifty throw.