Preheat the oven to 425°F for roasting the green beans.
Season the chicken breast with salt and pepper on both sides.
Heat a non-stick skillet over medium-high heat and add olive oil. When the oil is hot, add the chicken breast and sear for about 3-4 minutes per side until a golden crust forms, then lower the heat and continue cooking until the chicken reaches an internal temperature of 165°F.
Meanwhile, peel and dice the Russet potato into evenly sized chunks. Place them in a pot, cover with water, add a pinch of salt, and bring to a boil. Cook until the potatoes are tender, about 15 minutes.
For the mashed potatoes, drain the potatoes and return them to the pot. Add the minced garlic, skim milk, and butter. Mash until smooth and creamy, adjusting salt and pepper to taste.
Toss the green beans with a little olive oil, salt, and pepper, then place them on a baking sheet. Roast in the preheated oven for about 12-15 minutes until they are tender and slightly caramelized.
Plate the dish by slicing the chicken breast, spooning a serving of creamy garlic mashed potatoes, and adding a side of roasted green beans. Enjoy your nutritious, balanced meal!