Place the linguine in 2-1/2 quarts of already-boiling unsalted water and cook until tender, 9 to 11 minutes.

Combine the flour, salt, and pepper in a zipper-top plastic bag and shake to mix. Cut the chicken (fresh or partially defrosted) into bite-size pieces, drop them into the bag, and shake to coat.

Heat the oil in a 12-inch nonstick skillet over medium heat. Add the chicken and cook for 2 minutes, stirring from time to time. Peel and thinly slice the onion. Add them to the skillet along with the mushrooms and cook until the vegetables are softened and the chicken is no longer pink, 3 to 4 minutes.

When the linguine is tender, drain and cover to keep warm.

Add the wine to the skillet and heat, stirring and scraping to loosen any bits stuck to the pan bottom.

While the sauce heats through, place some linguine on each serving plate. Top with the sauce and serve.