Preheat your oven to 400F to prepare it for roasting the vegetables.
Chop the red bell pepper and red onion into bite-sized pieces, then seed and chop the jalapeno according to your heat preference.
Spread the chopped bell pepper, onion, jalapeno, and frozen corn onto a sheet pan; spray lightly with olive oil spray then season everything with kosher salt before roasting.
While waiting for the vegetables to roast (about 20-25 minutes), combine light mayo, Greek yogurt, lime zest and juice, cumin, paprika, additional kosher salt, and chili powder in a mixing bowl; whisk until well combined.
Once roasted vegetables have cooled slightly, chop cooked chicken breast into small chunks; add everything into the bowl along with chopped scallions and cilantro for freshness.
Gently toss all ingredients together until evenly coated in creamy dressing; finish by sprinkling Cotija cheese on top before serving chilled or at room temperature.