Preheat your oven to 400°F (200°C). Scrub the Russet potato clean, pierce it several times with a fork, and bake for 45-50 minutes until the center is tender.
While the potato bakes, place the ground turkey in a non-stick skillet over medium-high heat. Break it apart with a spatula and cook until browned and no longer pink.
Stir the tomato paste, chili powder, cumin, garlic powder, onion powder, sea salt, black pepper, and 0.25 cup of water into the turkey. Reduce heat to low and simmer for 5-7 minutes until the sauce has thickened into a hearty chili.
Once the potato is cool enough to handle, slice it in half lengthwise. Scoop out the interior flesh, leaving about a 1/4-inch thick shell of potato against the skin.
Place the potato skins on a baking sheet lined with parchment paper. Spoon the turkey chili evenly into the hollowed skins and top with the shredded sharp cheddar cheese.
Switch the oven to the broil setting and place the skins on the top rack for 2-3 minutes, or until the cheese is bubbly and the edges of the potato are crisp.
Remove from the oven and top each skin with a dollop of plain Greek yogurt and a sprinkle of sliced green onions before serving.