To make avocado crema: mash avocado until smooth. Stir in sour cream, lime juice and salt. Set aside.
In a large bowl, combine the ground beef and chorizo. Form into 4 patties and rub lightly with olive oil. Sprinkle each side with 1/2 tablespoon taco seasoning. Grill until cooked through (be careful when flipping as they may fall apart easily). Top each burger with 1/4 cup pepper jack and allow to melt.
Place buns on grill to toast. Place burgers on bottom buns. On the top bun spread with avocado crema then top with lettuce, tomato and tortilla strips.