Add 1 Tbsp olive oil to a large saucepan over medium heat (to cut down on dishes, use the same saucepan you're going to cook the risotto in). Sprinkle both sides of chicken breasts with ½ tsp salt and ½ tsp pepper and place in saucepan. Cook for 5-7 minutes on each side until golden and cooked through.
Remove chicken to cutting board and once cool enough to touch, slice chicken into bite-sized pieces.
While chicken is cooking, in a small saucepan over medium heat, bring diced tomatoes in juice and chicken broth to a simmer. Lower heat and keep mixture warm.
In the same saucepan you cooked the chicken in, add remaining 1 Tbsp olive oil. Add diced onion and cook for about 5 minutes until soft. Add garlic and cook for another minute.
Add arborio rice to the saucepan and cook for about 2 minutes, stirring a bit, until it’s translucent around the edges.
Stir in about 1 ½ cups of the tomato broth and stir occasionally until it has absorbed into rice completely, 3-4 minutes. Continue adding the mixture ¾ cup at a time, stirring after each addition, and waiting to add more until liquid is all absorbed. Stir occasionally. Rice should be creamy and al dente when done.
Add diced chicken, ¼ tsp salt, ¼ tsp pepper, dried basil, cherry tomatoes, mozzarella pearls, grated parmesan, fresh basil, and butter to rice and stir until well-combined and warmed through. Taste and add more salt if desired.
Serve risotto on plates or in bowls and top each serving with crispy panko topping and more parmesan cheese, if desired.