Preheat oven at 425
Slice peppers in half and place on baking sheet in oven to roast. Around 15 minutes or until charred. Remove and let cool. Roughly dice.
Slice the squash into rounds and place in one layer on parchment paper lined baking sheet. Toss with tbls of olive oil. Roast in oven until golden brown. Salt squash and gently toss to make sure all are coated.
In a medium sauté pan, sauté onions in tbls of olive oil until translucent. Add diced peppers.
In a casserole dish, layer squash, then corn, then onion/pepper mix, then shredded jack cheese. Add another layer. Top with Tajin
Bake cassarole until cheese in melted. Approx 15 to 20 minutes