Combine carrots, radishes, onion, vinegar, sugar and salt in a sealable plastic bag. Turn to coat. Set the bag in a shallow dish and marinate in the refrigerator for 1 hour.
Stir mayonnaise and Sriracha in a small bowl. Drain the pickled vegetables (discard marinade).
Spread 1 Tbsp. of the mayonnaise mixture on each tortilla. Top with lettuce, chicken and pickled vegetables and roll up. Wrap and refrigerate for up to 24 hours. Serve drizzled with more Sriracha, if desired.
Sugar substitute: We do not recommend a sugar sub for this recipe.
2 1/2 lean protein, 1 1/2 starch, 1 fat, 1 vegetable