Preheat a grill or grill pan on medium heat.
In a bowl, whisk together the ingredients for the marinade. Season with salt and pepper to taste.
Cook the chicken: Brush one side of the chicken with the marinade and season with salt and pepper. Then place that side down on the grill or grill pan. Brush the top side with marinade and season with salt and pepper. Cook on one side about 6 minutes until nicely marked then flip over and brush with marinade again. Cook for about 6 minutes to an internal temperature of 160 degrees. While the chicken is cooking, prep onion and corn per instructions above.
If using a grill, grill the corn on all sides until nicely charred and tender. If using stovetop, heat a saucepan of salted water to a boil. Add the corn and cook for 3-5 minutes.
Once the corn is cooked, lather with butter and lightly season with salt.
Brush the inside of each roll with the marinade. Lightly grill or toast to golden brown. Then set aside.
Once the chicken is cooked, set aside to rest for 2 to 3 minutes.
Make the sandwich: Spread mayo on the inside of both halves of the bread. Layer with lettuce, chicken, cheese, and onion.
Serve: Cut sandwich in half and enjoy with corn and lemonade.