Preheat large, nonstick sauté pan on medium 2–3 minutes. Season chicken with pepper and ½ teaspoon salt (wash hands). Place 2 tablespoons oil in pan; add chicken and cook 12–14 minutes, turning often, until well-browned and 165°F. Remove from pan and cover to keep warm.
Meanwhile, combine vinegar, honey, and Italian seasoning in small saucepan on medium-low. Simmer 5–6 minutes until mixture has thickened and reduced by two-thirds.
Halve sprouts, removing and discarding tough root ends. Place in microwave-safe bowl; cover and cook on HIGH 4 minutes. Halve and core pear, then cut into bite-size pieces. Add pears and squash to sprouts; cover and microwave on HIGH 4 minutes or until sprouts are tender. Drain well.
Return sauté pan to heat on medium-high; add remaining 1 tablespoon oil, sprouts mixture, and remaining ¼ teaspoon salt. Cook 3–4 minutes, stirring occasionally, until mixture is lightly browned. Slice chicken; arrange over sprouts mixture, then drizzle with balsamic sauce. Serve.