I don't think it's them coming from different political sides. Russia was involved in 2 wars with Chechnya. The 1st one was not so long after the Soviet Union broke up and the Russians got a bit of a hiding in Chechnya and other regions in the Caucasus. That didn't go down well with the Russians as they were sending conscripts to fight Chechen's who were more advanced in warfare than them - though Grozny still got pummeled.
When Putin came into power the 2nd Chechen war started and the Russians had their shit together more, and they (the Chechen's) were fighting a losing battle until Putin gave them an ultimatum to get bombed to pieces or put a stop to it all. Kadyrov's father was put in charge and in turn Putin's puppet in the region and got rid of the Chechen separatists who were still opposed to Russia occupying Chechnya.
Kadyrov's father got assassinated and then the purge of the separatists went into full swing when his son got put into power. But even before that, the Chechen's, Dagestani's, Ingush and other's from the region were fighting the Russians for centuries. I suppose you could say that Kadyrov and his supporters are 'turncoats' given the history, while those still opposed to Russia have gone into exile.
I'm just guessing on Artem's buddy's part. I know nothing of his background or if he does or doesn't live in Chechnya still. For Nurmagomedov's buddy, who is licking Kadyrov's boots - and probably is doing so to stay alive - to say he's not a Chechen is a bit daft.
I'd bet anything if Russia went to shit anytime soon, the Chechen's wouldn't be pledging their allegiance to Russia anymore and the region becomes unstable again.