Season the chicken with salt and black pepper and heat 1 tablespoon olive oil in a deep skillet over medium-high heat.
Cook the chicken for 3 to 4 minutes per side, until it reaches 165°F, then transfer it to a clean plate.
Add the remaining oil and onion and cook for 3 minutes before stirring in the orzo for 1 minute.
Add the tomatoes and broth and simmer for 10 to 12 minutes, stirring several times, until the orzo is tender.
Stir in the Parmesan and basil, return the chicken and warm it for 1 minute in the tomato orzo.