Reading about the Afghan war earlier, and a thought struck me that there were probably Mujahideen veterans from both wars.
Just realized my strange title. I am meaning specifically veterans from the Soviet Union deciding to serve in the NATO war, be it from immigrating and becoming a citizen or for any reason really.
Layman here with absolutely no credentials, but yes, there were Estonian troops who had fought in both wars.
Although it won't go into much detail, here is an excerpt from Toby Harnden's Dead Men Risen (page 251): "Theirs was martial culture forged through the domination of the big powers. The grandfathers of some of the troops had been members of the Waffen SS during the occupation of Estonia by Nazi Germany from 1941 to 1944. A few members of A company had fought in the Soviet army in Afghanistan following the Russian invasion of 1979. Now they found themselves alongside Afghan soldiers who had fought against them in the Mujaheddin."