Heat 1 tablespoon of the olive oil in a large, deep, oven-proof skillet over medium-high heat.
Add the sweet potatoes and season with 1/2 teaspoon of salt and 1/4 teaspoon of ground black pepper. Cover and let the sweet potatoes cook, stirring occasionally, until just fork tender, about 7-10 minutes.
Once the sweet potatoes are fork-tender, toss in the garlic, onion, and peppers. Season with 1/2 teaspoon of the salt, 1/4 teaspoon of ground black pepper, and the Italian seasoning.
Cook an additional 3-4 minutes until the onions and peppers are just soft, then transfer the vegetables to a plate or bowl.
Preheat oven to 350°F.
Add the remaining tablespoon of olive oil and the ground turkey to the skillet oven medium heat. Season with the remaining teaspoon of salt and 1/4 teaspoon of pepper.
Cook, breaking up with a spoon or spatula, until no longer pink in the center, about 10 minutes.
Add the vegetables back to the skillet and toss to mix.
Top with the shredded mozzarella cheese.
Place the skillet in the oven for about 5 minutes to melt the cheese.
Remove the skillet from the oven and top with fresh sliced green onions or parsley, if desired.