Preheat oven to 400°.
To prepare pork, place first 4 ingredients in a food processor; pulse until nuts are finely chopped. Place breadcrumb mixture in a shallow dish. Place egg whites in a shallow dish. Sprinkle pork with 1/4 teaspoon salt and 1/4 teaspoon black pepper. Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add pork; cook 6 minutes, browning on all sides. Cool slightly. Dip pork in egg whites; dredge in breadcrumb mixture. Place pork on a broiler pan coated with cooking spray. Bake at 400° for 30 minutes or until a thermometer registers 155°. Let stand 5 minutes. Cut into 1/4-inch-thick slices.
To prepare sauce, heat oil in a medium saucepan over medium-high heat. Add shallots; sauté 3 minutes or until lightly browned. Stir in wine, vinegar, honey, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Bring to a boil; cook until reduced to 3/4 cup (about 3 1/2 minutes). Combine milk, 1 tablespoon thyme, and flour in a small bowl, stirring with a whisk. Add milk mixture to pan; bring to a boil, stirring constantly. Cook 1 minute, stirring constantly. Serve sauce with pork. Garnish with thyme sprigs, if desired.