The creaminess of risotto makes it an instant comfort food, but the addition of sauteed summer squash and gently cooked, pencil-thin asparagus drives up the nutritional value too.
Combine broth and 3 cups water in a saucepan; bring to a simmer over medium heat.
Meanwhile, season chicken with salt and pepper. Heat a large, straight-sided skillet over medium-high. Melt 1 tablespoon butter. Cook chicken, flipping once, until golden brown in places and just cooked through, 4 to 5 minutes. Transfer to a plate. Melt 1 tablespoon butter in skillet. Add squash in a single layer, season with salt and pepper. Cook, flipping once, until browned in places and tender, 3 to 4 minutes. Transfer to a plate. Melt 1 tablespoon butter in skillet. Add onions; season with salt and pepper. Cook, stirring occasionally, until translucent, 2 to 3 minutes. Add 1 tablespoon butter to skillet and melt, then add rice and cook, stirring a few times, until translucent and nutty, about 1 minute.
Add wine to skillet and boil, scrapping browned bits from bottom of pan, until mostly evaporated, about 1 minute. Ladle enough broth into skillet to just cover rice. Simmer until almost evaporated, stirring constantly, and adding more broth, one ladleful at a time, until rice is creamy but still very al dente, 18 to 20 minutes (you will still have some broth remaining in saucepan). Stir in asparagus and a ladleful of broth. Continue cooking and stirring constantly until rice is al dente and asparagus is crisp-tender, 4 to 5 minutes. Remove from heat.
Thinly slice chicken and return to skillet with accumulated juices, squash, and cheese, gently stirring to combine. Stir in more broth, a little at a time, until risotto is creamy and sauce evenly coats asparagus and chicken. Season with salt and pepper. Serve immediately topped with more cheese.