I was not aware that NVidia chips were found in some Russian drones. I can confirm that accusation with some light Googling that shows reliable news sources. Those chips aren't very special. You can buy dev kits on Amazon.com[1]. So, I assume someone is buying 1000s in a friendly country, then smuggling them to Russia.

[1] https://www.amazon.com/NVIDIA-Jetson-Orin-64GB-Developer/dp/...