Tomato Parmesan Risotto

​5 cups low-sodium chicken broth
2 Tbsp. extra-virgin olive oil, plus more for drizzling
1 medium onion, finely chopped
3 garlic cloves, thinly sliced
1 Tbsp. tomato paste
2 cups cherry tomatoes or chopped large tomatoes
¼ tsp. freshly grated nutmeg (optional)
1 cup arborio or carnaroli rice
Kosher salt
2 Tbsp. unsalted butter
2 oz. finely grated Parmesan (about 1 cup), plus more shaved for serving
Freshly ground black pepper

 Bring broth to a simmer in a medium saucepan; keep warm over medium-low heat until ready to use.
 Meanwhile, heat 2 Tbsp. oil in a large saucepan over medium. Add onion and cook, stirring often, until golden and very soft, 8–10 minutes. Add garlic and cook, stirring, until softened, about 1 minute. Add tomato paste and cook, stirring often, until it darkens slightly and begins to stick to pan, about 2 minutes. Add tomatoes and nutmeg, if using, and cook, stirring occasionally, until some of the tomatoes begin to burst, about 2 minutes.
 Stir in rice; season with salt, and reduce heat to medium-low. Cook, stirring, until some grains are translucent, about 3 minutes. Ladle in 2 cups broth and simmer, stirring frequently, until completely absorbed, 8–10 minutes. Ladle in another 2 cups broth and continue to cook, stirring frequently, until rice is cooked through and most of the broth is absorbed, 12–15 minutes.
 Add butter, 2 oz. Parmesan, and remaining 1 cup broth and cook, stirring constantly, until risotto is very creamy looking, about 4 minutes. Taste and season with more salt if needed. Divide risotto among bowls. Top with shaved Parmesan and lots of pepper and drizzle with more oil.