Chuck used to have a lifetime guaranteed job with the UFC for doing nothing. He got a yearly salary.
When Zuffa was bought by WME, they got rid of Chuck and a bunch of other people to save money.
Forrest Griffen had that same lifetime deal with Zuffa, but he actually showed up to the office everyday looking for something to do, so they kept him on the payroll. That's why you see him on commercials and stuff. He's also on videos helping fighters and the Performance Institute.