Pound chicken breasts between sheets of waxed paper. Mix gruyere cheese, pesto, pine nuts, and green onions in a small bowl.
Spread 2 tablespoons of the cheese mixture on top of each chicken breast and roll tightly. Dredge chicken breasts in flour. Saute chicken breasts in heated oil at medium-high heat until golden brown, turning occasionally, for approximately 6 minutes.
Place chicken in pan and bake until chicken is tender and cooked through, about 20 minutes.