Peel the Russet potato and cut into 1-inch cubes, then place them in a pot of salted water and boil for 12-15 minutes until fork-tender.
While potatoes boil, season the chicken breast 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.
In a small pan, melt the ghee over low heat and add the minced garlic, sautéing for 1-2 minutes until fragrant but not browned.
Drain the potatoes and return them to the pot, then add the sautéed garlic ghee, Greek yogurt, chicken broth, and the remaining salt and pepper.
Mash the potato mixture until smooth and fluffy using a hand masher or whisk.
Slice the cooked chicken breast into strips.
Plate the garlic mashed potatoes, top with the sliced chicken, and garnish generously with freshly chopped chives.