Heat olive oil in a large skillet over medium heat.
Season chicken breasts with garlic powder, onion powder, salt, and pepper.
Add chicken to the skillet and cook until browned and cooked through, about 6-8 minutes per side.
Pour in the chicken broth, cover, and simmer for 15 minutes.
Remove chicken from skillet and shred using two forks.
Return shredded chicken to the skillet with remaining broth to keep it moist.
Peel and chop the russet potatoes into uniform pieces.
Boil potatoes in salted water until tender, about 15-20 minutes.
Drain and return potatoes to the pot, then mash until smooth.
Add milk and butter to the potatoes, mixing until creamy.
Season mashed potatoes with salt and pepper to taste.
Serve shredded chicken over mashed potatoes, garnished with parsley.