Season chicken pieces evenly with half of the salt and black pepper. Heat olive oil in a large skillet or Dutch oven over medium-high heat. Add chicken and sear until golden on all sides, about 5 to 6 minutes. Transfer cooked chicken to a plate and set aside.

Reduce heat to medium. Add the diced yellow onion to the skillet and sauté for 3 to 4 minutes until softened. Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Add the rinsed long-grain white rice to the pan and toast, stirring constantly for 1 to 2 minutes to coat the grains in oil and aromatics.

Pour in the chicken broth and stir in half of the basil pesto along with the remaining salt and pepper. Scrape any browned bits from the bottom of the skillet. Bring the liquid to a rolling boil.

Return the seared chicken and any accumulated juices back into the skillet. Stir gently, reduce heat to low, cover with a tight-fitting lid, and simmer for 15 minutes without lifting the lid.

Remove the skillet from heat. Uncover and drop halved cherry tomatoes on top. Stir in the remaining basil pesto. Cover again and let rest off the heat for 5 minutes to let the rice fluff and tomatoes warm through.

Fluff the rice gently with a fork, sprinkle with grated Parmesan cheese, and serve warm.