It appears to be plywood with 2x2 covering the joints and over 16"oc stud layout. If so, you already have the shear value (I thought it was B&B siding from your stucco/chimney post answered earlier). Your climate may warrant plastic sheeting next to the drywall, check at an outlet/switch box. If so, NO faced (plastic/foil) rigid insulating sheeting on the exterior to trap moisture from exiting. Use XPS, maybe; depends on plastic vapor barrier or retarder inside, describe the wall make-up, please.