Meanwhile, prepare grill to medium-high heat.
Season chicken breasts evenly on both sides with Stubb’s Chicken Spice Rub. Cook chicken over direct heat on prepared grill for 6-8 minutes per side or until chicken reaches an internal temperature of 165 degrees. During the last 2 minutes of cooking, lay a slice of cheese on top of each piece of chicken.
Spread prepared Suiza Sauce on each side of the sandwich buns and place grilled chicken on prepared buns. Top as desired with avocado, tomato, red onion and lettuce.