Heat 2 tablespoons olive oil in a large stockpot or Dutch oven over medium heat. Add diced onion and sauté 2 minutes until beginning to soften.

Add carrots, celery (including reserved leaves), and fresh thyme. Sauté 4 minutes, stirring occasionally.

Add cubed chicken, season with salt and pepper, and pour in 4 cups chicken stock. Partially cover and simmer for 20 minutes or until chicken is cooked through and vegetables are tender.

While soup simmers, cook fideo separately: In a medium pot, bring remaining 4 cups chicken stock to a boil. Add fideo noodles and cook until al dente according to package directions (usually 7-8 minutes). Reserve 2 cups of the cooking liquid before draining.

Drain cooked fideo and transfer to a medium bowl. Toss with remaining 1 tablespoon olive oil to prevent sticking. Cover and set aside.

Just before serving, add cooked fideo to the soup pot. Stir to combine and remove from heat.

Stir in lemon zest, lemon juice, and nutmeg. If soup seems too thick, add some of the reserved fideo cooking liquid to reach desired consistency.

Divide among serving bowls and top with freshly grated Parmesan cheese. Garnish with fresh cracked pepper, parsley, and thyme if desired. Serve with crusty bread and/or garden salad.