Season chicken breasts with salt and pepper.
Heat olive oil in a large skillet over medium heat, then cook chicken for about 5 minutes per side until it reaches an internal temperature of 165°F.
Remove cooked chicken and set aside.
Lower heat to medium-low, add butter and chicken base to the skillet, stirring until melted.
In a small bowl, combine flour, onion powder, garlic powder, salt, and pepper.
Add this mixture to the pan to form a roux; stir continuously for about 30 seconds.
Gradually pour in chicken stock while scraping the bottom of the pan to incorporate flavor.
Add water and whisk until smooth; simmer until thickened.
Shred the cooked chicken if desired and return it to the gravy along with any juices.
Let simmer for a few minutes before serving over mashed potatoes.
