Here's a mini-guide to SoCal Mexican chains I wrote in another thread:
If you're headed to Los Angeles or Orange County and are itching for chain Mexican food, here are some that don't suck:
Invalid Link Removed - Probably the biggest, most widespread chain. Not the best Mexican food but dependable and extremely satisfying on your home from the late gig. Beware of imitators like Adalberto's, Edbertos, etc who all seem to have logos very similar to Alberto's.
EDIT: Apparently, Alberto's was a spin-off of Roberto's in the San Diego area. I've never been to a Roberto's but if it has the same pedigree as Alberto's it has to be good!
King Taco - Another big chain. I've never been big on King Taco but it's popular.
Invalid Link Removed - Back in the day (i.e. the 90s), tacos were $0.50 each. They were small but tasty and most importantly, cheap. I think the last time I went into one, tacos were $1. Still not a bad deal.
Tacos Nazo - Not a huge chain but KILLER fish tacos!
Pepe's - Small, mostly Orange County chain. It was the closest Mexican to were I went to college so I spent plenty of time there.
EDIT: I forgot this place in my original post: Invalid Link Removed - Another Orange County chain. Tasty!
Not included are the soulless, quasi-Mexican, not quite as mega as Taco Bell/Del Taco chains like Chipotle, Qdoba, Rubio's, etc. Don't waste your time at places like that. They're not SoCal!
Of course, the best Mexican food will be found in the small mom-and-pop restaurants that we SoCal folk like to wax poetic about. You *could* spend your time sitting in our traffic, trying to hunt down that elusive taco or burrito, but it might be easier to just hit one the above chains.