In a bowl combineStarkist Premium White Chicken, Slap Ya Mamma Cajun Pepper Sauce,melted butter, cream cheese, ranch, chopped green onion, salt, and pepper. Mix until everything is fully incorporated.
Spread mayo in an even layer on each slice of sourdough bread. Flip two slices over and divide the chicken mixture and spread in an even layer. Top with a slice of mozzarella and cheddar cheese. Top with remaining slice of sourdough, mayo side up.
Heat a skillet over medium heat and add butter to melt. Place each sandwich in the skillet. Let cook for about 5 minutes, until the bread is golden. Flip and cook the other side until golden.