Preheat broiler with rack 3 inches from heat. To make crema: Combine the sour cream and adobo sauce in a small bowl, whisking well; set aside and allow flavors to meld. Meanwhile, combine jicama, cabbage, carrots, cilantro leaves, lime juice and zest, 1 tablespoon olive oil, and 1/4 teaspoon each of salt and pepper in a medium bowl; toss well. Chill until ready to use.
Place the fish in a broiler pan; brush with remaining teaspoon olive oil. Sprinkle with the chili powder, paprika, cumin, and remaining 1/2 teaspoon each of salt and pepper. Broil until the fish is cooked through and slightly charred around edges (6-8 minutes). Remove fish from oven; flake with a fork.