Heat the large skillet over medium heat and add the olive oil.
Add the cubed chicken and cook until browned and cooked through, about 5–7 minutes; remove with a slotted spoon and set aside.
Add the diced onion, sliced celery, diced green pepper, and minced garlic to the skillet and cook over medium heat until the vegetables begin to soften, about 5 minutes.
Return the chicken to the skillet, then sprinkle the paprika, crushed red pepper flakes (if using), cayenne, and oregano over everything; stir to combine.
Add the petite diced tomatoes and bay leaves, stir well, then bring to a gentle simmer.
Simmer uncovered for 10–15 minutes to meld flavors and reduce slightly; discard bay leaves before serving.