Start by heating your oven to 425 degrees Fahrenheit.
Coat the chicken with half the olive oil, garlic powder, Italian seasoning, and some salt.
Heat the remaining olive oil in a large oven-safe pan over medium-high heat.
Cook the chicken in the hot oil, turning once, until it’s browned and just under fully cooked, about 8-10 minutes.
If the pan darkens too quickly, splash in a bit of water to help.
Remove the chicken and let it rest on a cutting board.
Add a tablespoon of butter to the pan and melt it, scraping up any browned bits left from the chicken.
Sauté the sliced shallots in the butter until they soften, about 2-3 minutes.
Stir in the minced garlic and cook until fragrant, around 1-2 minutes.
Add the rest of the butter and let it melt completely.
Sprinkle the flour over the butter and stir to create a roux paste.
Gradually whisk in the chicken broth, milk, and heavy cream over medium heat.
Raise the heat a bit and whisk until the sauce thickens and starts to bubble.
Turn off the heat and chop the chicken into bite-sized pieces.
Add the chicken and uncooked gnocchi into the sauce, stirring until everything is coated.
Sprinkle the mozzarella and parmesan evenly over the top.
Transfer the pan to the oven and bake for about 12-15 minutes until the cheese is bubbly and golden in spots.
Rotate the pan during baking if needed for even browning.