What I've learned being in Las Vegas: everything is about 50% more expensive here. Carnitas plate? $22. Carne asada burrito? $18.
So pricing aside, the Cantina is a great restaurant. Nice ambiance for drinks and Mexican food. And they actually serve Mexican corn. Yum. Don't think about how it is 3x the cost of getting it on the street in Chicago or Oakland. I said don't think about it.
Just enjoy your tasty tacos with your large margarita. They are a margarita bar so don't miss out! And they make up for the pricey-ness of the food with generous glasses of alcohol.