Preheat your oven to 400°F (200°C).
Season the chicken breast evenly with the dried oregano, half of the sea salt, and half of the black pepper.
Place the chicken on a parchment-lined baking sheet and roast for 20-25 minutes, or until the internal temperature reaches 165°F.
While the chicken roasts, peel and dice the Yukon Gold potato into 1-inch cubes.
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.
During the last 5 minutes of potato cooking, steam the broccoli florets in a steamer basket over boiling water until they are bright green and tender-crisp.
Drain the potatoes and return them to the pot. Add the Greek yogurt, ghee, and minced garlic clove.
Mash the potatoes until smooth and creamy, then stir in the fresh chopped chives and remaining salt and pepper.
Slice the roasted chicken breast and serve immediately alongside the garlic mashed potatoes and steamed broccoli.