When ready to grill, place foil on gas grill over medium heat or on charcoal grill 4 to 6 inches from medium coals. Sprinkle walleye fillets with salt and pepper. Place fillets on foil; cook 8 to 12 minutes or until fish flakes easily with fork, turning once. During last minute of cooking time, top fillets with pecan butter. Remove fillets from heat; place on serving platter. Sprinkle with remaining 2 tablespoons pecans.