It depends what you eat; obviously eating a lot of flour-based products with lots of preservatives is NOT healthy. Even tortillas, even though wraps are "so in" right now, are probably bad for you.
The chips are usually deep-fried; obviously, that's not good for you.
Why don't you take a cue from REAL Mexicans and eat things like tuna salad? Ask one of the workers there about the tuna salad with carrots and corn in it. Mexican food can be VERY healthy; after all, they're used to markets with fresh food and their cooking utilizes those natural ingredients over fake stuff.
But a restaurant's "Mexican" food .... it's probably no good for you, no matter how wonderful it tastes. And I know it does.