Hi red, welcome.
Gotta tell you from my experience with Mexican recipes, even in Mexico, they just give you the basics like the pollo and espincaca (spinach) and leave you without a clue to the additives.
But you have the basics, the chiicken, cream cheese (and mixed with sour cream works), and the spinach.
Try a batch on your own. And go back to the restaurant and see if you can detect a difference and try to determine what that is.
Have no better idea, sorry.
Before criticizing a person, walk a mile in his shoes - then you are a mile away and you have his shoes!