Departing Mexico City airport to USA with permanent resident

We are PRs also and did the departure ZIH to MEX to USA in April.
Domestic flight from ZiH so no need to do anything. From MEX we went to check our one bag on Aeromexico. There was an immigration desk right there that put a little sticker on our passport that got us through to the boarding. Easiest system we’ve encountered getting out of Mexico.
Don’t worry it will all work out.