Peel and cube the russet potato into 1-inch pieces.
Place the potato cubes in a pot of cold water with a pinch of salt, bring to a boil, and cook for 12-15 minutes until fork-tender.
While the potatoes boil, season the chicken breast evenly with half of the sea salt and black pepper.
Heat avocado oil in a skillet over medium-high heat and sear the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
Mince the garlic cloves and finely chop the fresh chives and parsley.
Drain the cooked potatoes and return them to the warm pot.
Add the ghee, minced garlic, Greek yogurt, and the remaining salt and pepper to the potatoes.
Mash the potato mixture until smooth and creamy, then fold in the fresh chives and parsley.
Slice the seared chicken breast and serve it immediately over the warm buttery garlic mashed potatoes.