Combine mayonnaise, sour cream, ranch seasoning, lime juice and chipotle chile powder and whisk together until smooth.
Chill in fridge while making burgers for flavors to meld.
To make Southwest Burger Patties
Combine ground beef, green chiles, chili powder, cumin, garlic powder, salt, pepper and cayenne pepper (optional).
Use your hands to work the mixture to evenly distribute the seasonings and green chiles. Try to work the meat as gently as possible and as little as possible to do this. Overworking the meat can make the burgers less tender.
Split meat into 8 equal parts and form into balls, then flatten into patties.
Cook the burger patties in a pan or on the grill for 3-4 minutes per side, or until cooked to your desired doneness.Top with colby jack cheese 1 minute before taking the burger off the grill.
To assemble the Southwest Burgers
Optional: Toast the inside of each hamburger bun on the grill or griddle.
Place a leaf of lettuce on the bottom half of the hamburger bun. Add the burger patty, then top with tomato, onion, and avocado, or your preferred burger toppings.
Spread 1 tablespoon of Southwest sauce on the inside of the top of each bun. Place the tops on the buns. Serve immediately.