Place chicken stock in a medium saucepan. Bring to a simmer (do not boil). Keep warm over low-medium heat.
Heat a large nonstick skillet over medium heat. Add 1 tablespoons olive oil and 1 tablespoon of butter to pan; swirl to coat. Add onions and cook for 3 minutes and add garlic. Stir in rice, and cook for 3-4 minutes, stirring constantly. Increase heat to medium and add wine. Add 1/2 cup stock and cook 3-5 minutes or until liquid is nearly absorbed, stirring constantly. Continue adding remaining stock, 1/2 cup at a time, stirring constantly until each portion of stock is absorbed before adding the next. Add shrimp when last portion of stock is added. Cover pot and remove from heat to allow the shrimp to cook till pink. Right before you serve the risotto, stir in the cheese and thyme. Season with salt and black pepper. Top with additional feta.