Heat 1 tbsp vegetable oil in a 10-inch skillet over medium-high heat until the oil shimmers.
Add the chicken pieces in a single layer and cook, stirring occasionally, until no longer pink and browned on the outside, about 5–7 minutes.
While the chicken cooks, prepare the cooked white rice according to package instructions if it is not already cooked.
Pour the jarred butter chicken sauce into the skillet. Rinse the jar with a few tablespoons of water, add the rinse to the pan, and stir to combine.
If using, add the halved cherry tomatoes to the skillet, bring the sauce to a simmer, then reduce heat and simmer gently for 15 minutes.
Serve the butter chicken and sauce over the cooked white rice and sprinkle with chopped fresh cilantro.