Preheat the oven to 425 degrees. Slice the chicken breast into 4 strips. Submerge the chicken in the buttermilk, making sure to coat. In a shallow dish, mix together ¼ cup of the cornmeal and the panko bread crumbs and season with 1 t. salt and ¼ t. pepper. Coat each chicken strip in the bread crumb mixture and place them onto a greased baking sheet. Spray the strips liberally with cooking spray and bake for 10 minutes, turning halfway through, until chicken reaches 165 degrees.
Meanwhile, in a shallow dish mix together the remaining cornmeal, flour and ½ t. salt and ¼ t. pepper. Toss the onion slices in the flour mixture, making sure to separate the rings as you toss. Heat about ½ an inch of vegetable oil in a skillet until the oil shimmers. Add the onions to the oil and fry until golden brown, about 7 minutes. Remove with a slotted spoon and drain on paper towels.
Combine all of the dressing ingredients in a blender or food processer and blend until smooth. Taste and adjust seasonings if necessary.
In two large bowls, divide the lettuce mix, top with tomatoes, avocado and mozzarella cheese. Place 2 chicken strips on top of lettuce bed and top each with fried onions. Serve with dressing on top!