Place carrots in large saucepan or Dutch oven; add enough water to cover carrots. Cover; bring to a boil. Reduce heat to simmer. Cook 12 to 15 minutes or until tender. Drain.
Meanwhile, place pecans in small nonstick saucepan; cook over medium-high heat for 3 to 5 minutes or until lightly browned, stirring constantly. Remove pecans from saucepan; set aside.
In same saucepan, combine onion and butter; cook 2 minutes over medium heat or until onion is tender.
Stir in syrup; bring to a boil. Boil 5 minutes, stirring occasionally. Stir in pecans. Pour over carrots; toss gently to coat.