Heat olive oil in a skillet over medium heat. Season chicken with salt and pepper, then brown for 3–4 minutes per side.
Add diced onion and sauté until softened, about 4 minutes. Stir in garlic and cook 30 seconds.
Pour in red chile sauce and chicken broth. Bring to a simmer, then reduce heat and cook covered for 10–12 minutes, until chicken is cooked through.
Shred the chicken in the pan using two forks, stirring to coat in chile sauce. Adjust seasoning if needed.
Meanwhile, in a bowl combine corn, sour cream, mayonnaise (if using), lime juice, chili powder, cilantro, salt, and pepper. Mix until creamy and well combined.
Warm tortillas in a pan or oven until pliable.
Fill each tortilla with shredded chile chicken, top with a spoonful of creamy corn, and garnish with radish slices, queso fresco, and a squeeze of lime.
Serve immediately while warm and fresh.