Pulse pecans and breadcrumbs in a food processor until finely chopped; place in a shallow dish. Sprinkle fish with salt and pepper; coat fish with flour, dip in egg, and dredge in pecan mixture.
Melt butter in a large ovenproof skillet; reserve 1/4 cup. Brown fish in remaining butter over medium-high heat 3 minutes on each side. Transfer fish to serving plates, and drizzle with reserved melted butter. Combine lemon rind and remaining ingredients; pour over fish, serve immediately. Makes 4 servings.