Preheat the oven to 450 degrees F. Peel and half the onion, then cut into 1/3-inch slices. Cut the red pepper and zucchini into slices about the same thickness. Halve the mushrooms.
Drizzle olive oil over a large rimmed 13x18-inch sheet pan. Place the chicken thighs on the sheet pan. Then add the sliced onions, peppers, and zucchini. Sprinkle with salt, pepper, and dried Italian seasoning. Roast in the oven for 15 minutes.
Flip the chicken and vegetables over on the sheet pan. Add the mushrooms and minced garlic. Spoon the tomatoes and some of the sauce out of the can and place on the baking sheet. Drizzle the white wine over the top. Then sprinkle everything with salt, pepper, and more Italian seasoning.
Roast another 15 minutes, until the sauce is bubbling. Serve the chicken warm, with a side of vegetables and the pan sauce.