Heat the oil in a large Dutch oven or pot over medium-high heat until shimmering. Add the onion and sauté until softened and fragrant, about 3 minutes. Add the orzo and garlic, season with salt and pepper, and sauté until fragrant, about 1 minute.

Stir in the broth, tomatoes, and chickpeas and bring to a boil. Cover, reduce to a simmer, and cook, stirring frequently so that the orzo doesn’t stick, until most of the liquid is absorbed and the pasta is al dente, about 10 minutes or according to package instructions. (If the pasta isn’t completely cooked at this point, add another splash or two of broth or water to the pot and continue to simmer until it has.) Stir in the Parmesan cheese. Taste and season with salt and pepper as needed. Garnish with the chopped basil and additional grated cheese, if desired.