1 1/2 cups sour cream
1 tablespoon chopped canned chipotle chiles* (about 2)
2 tablespoons (packed) golden brown sugar
1 tablespoon smoked hot Spanish paprika (Pimentón de la Vera)**
2 1/4 teaspoons chili powder
1 1/2 teaspoons coarse kosher salt
1 1/2 teaspoons garlic powder
1 1/2 teaspoons onion powder
2 small zucchini, quartered lengthwise
1 red bell pepper, seeded, cut lengthwise into 3/4-inch-thick strips
2 tablespoons canola oil
1 pound skinless boneless chicken breast halves, each halved horizontally
12 5- to 6-inch-diameter corn tortillas, warmed
Cilantro Slaw
2 limes, each cut into 6 wedges