Heat 1 tablespoon olive oil in a large sauté pan over medium-high heat until shimmering.
Season the diced chicken lightly with salt and pepper, add to the pan, and cook undisturbed until golden on one side, about 3 minutes.
Rotate the chicken pieces so other sides can brown and continue cooking until cooked through, about 3 more minutes; transfer the chicken to a plate and tent with foil to keep warm.
Add the remaining 1 teaspoon olive oil to the pan, add the minced garlic, and sauté about 20 seconds until just fragrant and lightly golden.
Pour in the low-sodium chicken broth, scraping up any browned bits from the bottom of the pan, and bring the liquid to a boil.
Add the orzo, reduce heat to medium, cover the pan, and allow to simmer gently for 5 minutes.
Uncover, stir, and continue cooking uncovered until the orzo is tender, about 5 more minutes, stirring occasionally; some broth may remain for a saucy finish.
Return the cooked chicken to the pan, remove from heat, and stir in the Parmesan until melted.
Fold in the chopped sun-dried tomatoes and chopped basil, season with freshly ground black pepper, and add a little salt only if needed.
If the mixture is too thick, add additional broth to reach the desired sauciness, then serve warm.