The locals I worked with in New Mexico would make green chili stew from beef, pork or chicken. Generally the red chili dish was only made from beef.
We were getting packing house whole shrink wrapped pork loins for $.99 to $1.49 and whole prime rib roasts for $3.99/lbs out there.
I get whole pork loin in Texas and Louisiana (where I’m working now) for around $1.67 to $1.99 per lbs. Cut into chunks it makes great green chili stew or is great slow cooked in Chili Verde sauce...
Traditional is either no meat or mutton....but as I say that was a long time ago. I too make mine with pork (occasionally chicken for those who don’t eat pork)