Brewery Bar III
I'm not positive that this restaurant is strictly a Colorado-based chain, but Brewery Bar III in Lone Tree is excellent. I'm a stickler when it comes to red and green chile, and this place has the best I've found so far. I've been to numerous, more popular chains known for their authentic tastes, like the Rio or Los Arcos, but Brewery Bar III stands alone. The taste is fresh, has the perfect amount of "heat," and the cost is fairly priced!