Pat chicken dry and season with salt and pepper. Heat the oil in a large nonstick skillet over medium heat until the oil is shimmering. Add the chicken and cook for 6 minutes per side or until golden brown and cooked through.
Remove chicken to a plate and refrigerate until chilled, about 30 minutes then cut into 1/2-inch pieces.
Mix the mayonnaise, cheese, sour cream and lemon juice in a large bowl. Add the eggs, avocado and chicken; toss gently to combine.
Split bakery rolls in half and scoop out some of the center bread. Fill hollow with chicken salad. Top with crumbled bacon and a lettuce leaf. Enjoy!
Make ahead: The salad minus the avocado may be made and refrigerated up to 2 days in advance. Add the avocado just before serving.