Shepping nachas is a Yiddish expression; literally it means "scooping up satisfaction/pleasure"
What is really means is harder to express.
I googled 'shepping nachas' and came up with this definition, penned by Treppenwitz: 'shepping nachas' can be roughly translated as a combination of deriving great pleasure from something and being extremely proud of someone... for example; when a friend or loved one does something exemplary.
That about sums it up for me.
I am so proud of my son. He delivered a complex drasha and, once again, he spoke clearly and with confidence.
Even when the microphone made all sorts of annoying noises, my son kept his composure and did not lose his train of thought.
At one point in the drasha, he realized that he skipped something earlier on and he seemlessly inserted the relevant information so that he could make his next point.
He had full command of his subject matter and he presented it well.
I could not be any prouder.
Please daven (or send happy, healing thoughts) for RivkA bat Teirtzel.
With love and optimism,
GA 2016: Natan Sharansky (video)
3 minutes ago